Install and sign in
Open the official download page and choose your operating system. Install the desktop app, open it, and sign in with your ChatGPT account. For this walkthrough, use your account login; you do not need to create an API key.
Find the switcher
Look at the top-left menu. Select ChatGPT for Chat and Work, or Codex for building and technical tasks. Within ChatGPT, the Chat / Work control sits above the new conversation. The diagram beside this lesson lets you rehearse that choice.
Pick a small first task
Choose Chat for an explanation or a short draft. Choose Work when you want a document, spreadsheet, or other deliverable. Choose Codex when you want to build or change software. You can learn all three without deciding on one forever.
Use the controls you actually have
Start with the default model for a small exercise. Model choices, features, and usage depend on your account and workspace. If Work is missing, update the app and check your account or workspace access. You can still practise the first conversation in Chat.
Explain the difference between Chat, Work, and Codex for someone who has never used this app. Give one everyday example for each, in under 150 words.
Sources and availability
Checked 6 September 2026. Labels and access can vary by app version, account, and workspace. Practice examples are created for this guide.
OpenAI: Desktop quickstart OpenAI: Chat, Work and Codex