To delete your Grok chat history on grok.com/app and X, go to your chat...

https://charliekzxa221.huicopper.com/does-deleting-grok-history-reset-memory-or-custom-instructions

To delete your Grok chat history on grok.com/app and X, go to your chat settings and choose “Delete History.” Remember, this clears only chat messages—files and Imagine media must be deleted separately