The map first, then the controls
One app, different workspaces
The author’s desktop screenshots show everything in one app: choose ChatGPT or Codex, then switch between Chat and Work inside ChatGPT. You do not need to open another program each time. This does not mean every view automatically has access to the same files and connections.
Desktop app · account and settings
Teaching diagram based on the supplied screens from 19 October 2026, not an additional app screenshot. Names and availability depend on version, account and administrator. Codex also has other entry points, including the terminal and code editor.
Mode ≠ model ≠ plugin. A mode chooses how you work. A model is the engine doing the task. A plugin supplies instructions or tools. Changing the model does not connect your company drive.
Chat, Work and Codex: three ways of working in one app
In the app shown, you switch between ChatGPT and Codex. Chat and Work are two ways of working inside ChatGPT. Choose by outcome: a conversational answer, a finished deliverable or work on project files. Other app versions may differ.
Chat
An adviser at your desk
You ask, get an answer, follow up. You lead and see every step. Good for questions, brainstorming, drafts and comparisons.
Work
An assistant you hand a task to
You describe the outcome. ChatGPT plans, gathers information from files and tools, builds a file (document, spreadsheet, deck) and asks when something is missing. You review and approve.
Codex
A developer with access to the project
The same kind of agent, with a developer's view: you see commands, file changes (diff) and test results. Most useful for code and repositories.
Work and Codex have overlapping capabilities. The main difference is the view: Work speaks everyday language and hands over finished files, while Codex shows technical detail such as commands and code differences. Both draw on the same usage limits of your account.
Where to switch and where it runs
- In the desktop app, choose ChatGPT or Codex in the product selector. In ChatGPT, the switch above the composer changes Chat to Work.
- In the browser, Work runs in a managed cloud environment. In the desktop app, if it is enabled for your account or company, you can choose local work: on files, apps and the browser on your own computer.
- Cloud work can keep going after you close the app. Local work uses only what you grant access to on your computer. A company administrator can restrict either option.
Test yourself: which of the three do you pick?
Click an answer to see the reasoning. Look at the outcome, the sources and who checks the result.
Four common mistakes
- “Work is just a better Chat.” No. For a quick question or a rewrite, Chat is faster. Longer Work tasks use more of your limit because ChatGPT does more on your behalf.
- “Codex is only for developers.” You can also use it for everyday office work, but it shows technical detail. If you do not need that, Work is simpler.
- “The agent finished, so the result is right.” A finished file is a draft to check. Open it and verify numbers, names, dates and whether the right sources were used.
- “The tool sees everything or nothing.” The scope depends on what you upload, which tools you connect and what your administrator allows. Always check in the settings what a given task can access.
10-minute exercise: the same task twice
- Pick a small task from your own work, or use a fictional one: summarise two short meeting notes.
- Ask for it in Chat in one plain sentence. Note how many follow-up questions you needed.
- In Work, use the template below: outcome, sources, scope, requirements, what good looks like and where to stop.
- Compare both results. Which is easier to check? What in the second prompt reduced the follow-up questions?
Prepare [file type, e.g. a one-page summary] for [who will read it]. Sources: only the attached files [list]. Scope: [what it must contain, e.g. the three most important findings with evidence]. Requirements: separate facts from recommendations, flag numbers you cannot verify in the sources. A good result is: [one sentence on how you will know it is right]. Stop after a draft for my review - do not send anything.
No access to Work? Use the same template in Chat and ask for a draft. You will still learn to describe an outcome, which is the key skill.
Sources: the official “Use ChatGPT” and “Get started with ChatGPT Work” pages (learn.chatgpt.com), checked 18 October 2026. Feature availability depends on plan, platform, region and company settings.
Your app - Chat
This is what Chat looks like
In short ↳A clean screen with one box. You type a question and get an answer. Everything else sits at the sides and can be ignored for now.
Where to find it: ChatGPT (app) → Chat
Select the screenshot to enlarge it.
What you see on screen
- 1
Chat / Work switch
This is where you change mode. Chat is a conversation and a quick answer; Work is a task done on your files.
- 2
New chat
A blank page. Start a new chat for every new topic, because an old conversation drags its context along.
- 3
Pinned, Projects, Recent
Projects hold the files and instructions for one matter, e.g. a client. Recent is your conversation history.
- 4
'Ask ChatGPT' box
The plus on the left adds files and photos. Write as you would to a colleague: why, for whom, in what form.
- 5
Effort level (in the screenshot: High)
Higher effort may help with complex tasks but usually takes longer and does not guarantee correctness. Match effort to the task and check the result.
- 6
Microphone and voice
Dictate a question or talk by voice. Voice terms are covered in lesson 06.
How to use it - in plain words
Start with one simple question from your work and look at the answer. Then add context and compare.
You do not need every button. Three are enough: New chat, the text box and the plus for files.
Try it on your account
Open the app, click New chat and change the effort level. Ask the same question at two levels and compare time and quality.
Your app - Work
Work: 'What shall we work on?'
In short ↳Same screen, different mode. You do not ask here, you assign a task: pick a project, files and plugins, then set how hard the model should work.
Where to find it: ChatGPT (app) → Work
Select the screenshot to enlarge it.
What you see on screen
- 1
Work is on
The question and the box changed: instead of a conversation you get a place for a task to carry out.
- 2
Choose project, Files, Plugins
This is where you say what to work on and what to use. Without a project and files the model does not know your materials.
- 3
Access marker ('Full access')
The orange mark draws attention to the scope of permissions. Before you leave it on, check on your account what exactly it means.
- 4
Choose effort
Opens the level slider for the selected model.
- 5
Slider: Ultra, GPT-6 Astra
The screenshot shows the highest level (Ultra). Available levels and models depend on your plan, so your list may be shorter.
How to use it - in plain words
Give Work what takes more than a single answer: a report from files, organising materials, an analysis.
High effort takes more time and usage, so do not set the maximum 'just in case'. Start in the middle and raise it when the result is shallow.
Try it on your account
Switch to Work, pick a project or a file and click Choose effort. Check which levels you see on your account.
Your app - Codex
Codex: 'What are we building?'
In short ↳Codex looks similar but works on code and files. First you choose where it works: on this computer, in the cloud or remotely.
Where to find it: ChatGPT (app) → Codex
Select the screenshot to enlarge it.
What you see on screen
- 1
'Codex' header
The left column has the same sections as Chat, but the list holds coding tasks.
- 2
Work in: This computer / Cloud / Remote
This computer means files on your machine. Cloud is a separate environment. Remote connects to another device. Start with This computer.
- 3
Choose project
You point to the folder Codex should work in. Pick a small test folder.
- 4
'Assign anything' box
Describe the end result and how you will check it is done.
- 5
Approvals (in the screenshot: 'Approve for me')
This setting decides how many steps Codex takes without asking. At first pick the option where you confirm yourself; check the option names in your version.
- 6
Model and effort (GPT-6 Astra, Ultra)
The same choice as in Work. Availability depends on your account plan.
How to use it - in plain words
Codex is not only for developers. Ask it to organise files, build a simple page or write a script that does the boring work.
Always start in a test folder. Only when you have seen how Codex works, give it a real project.
Try it on your account
Open Codex, click 'Work in' and look at the three options. Pick a test folder and check the approvals setting before assigning anything.
Two files, two different prices
Fictional example: an approved 1 September price list says PLN 1200. An unapproved 10 October draft says PLN 1400. A newer date alone does not make a document authoritative.
Instruction for the project
Use approved sources for the proposal. For each price, give the filename, date and approval status. Flag conflicting drafts and ask the owner to confirm before using them.
What should a good answer say?
PLN 1200 from the approved list, with a note that a later draft proposes PLN 1400. Do not average prices or silently replace the approved value. Ask whether the draft has been approved.
No Projects access? Paste both fictional source descriptions into a chat and test the same instruction.
Part 02 - Advanced
Projects and Deep Research - two features that make a difference
Choose one topic from your work. Create a Project for it or request research with a specific question.
Projects
A separate 'workroom' with its own files and instructions. One project can collect materials for one client, department or process. Identify the current sources in each task and check which documents the answer uses.
- 📂 Keep relevant files together and identify the version that applies to the task.
- 📝 You set instructions per project: tone, style, format.
- 🔒 Check sharing and source access; a project name alone is not an access control.
Deep Research
ChatGPT itself plans the research, searches dozens of sources, reads reports and prepares a summary with links. Judge it by the quality and relevance of its evidence, not by the number of sources or speed.
- 🎯 You provide the topic and context, AI splits it into research questions itself.
- 🔗 A report with bibliography - you check every link.
- ⏱ Allow time for research and source review; check task status in your app.
More detailCompare Chat, Work and CodexOpen this if you are unsure which mode fits your task.
Choosing a tool
ChatGPT, ChatGPT Work or Codex - when to use which?
It is not a competition, just one ecosystem with different roles: ChatGPT for conversation, ChatGPT Work for longer projects, Codex for technical work.
ChatGPT
👨🏫 Advisor and analyst
“Think with me, explain, write, analyze.”
- Conversation, brainstorming, writing
- Analysis of data and documents
- Translations, summaries, offers
- You do the work - ChatGPT helps and explains
ChatGPT Work
🤖 Intern-executor
“Do this for me - fetch, check, send, repeat daily.”
- Executes specific tasks on its own
- Reads files, sends emails, updates CRM
- Connects to your apps (Slack, Gmail, GitHub...)
- Works 24/7 - even when you're not there
First you talk to ChatGPT and decide what to do. Then ChatGPT Work or the Codex view executes it for you - once or every day at the same time.