Go to Settings → Data controls → Export data in ChatGPT and request an export. OpenAI will email you a download link within a few minutes to a few hours.
Once downloaded, you have two options:
OpenAI-export.zip file above. This works but can be slow (the zip is often 500 MB+, mostly images and audio we don’t need).
conversations.json recommended — much faster. Extract the zip and find:User Online Activity/Conversations__….zippersonal/conversations/conversations.jsonA few quick questions about who you are. This helps us understand how different groups use ChatGPT. Every field is optional — leave anything blank you'd rather not answer.