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

https://echo-wiki.win/index.php/Why_Did_a_Deleted_Grok_Chat_Reappear_on_My_Other_Device%3F

To delete your Grok chat history on grok.com/app and X, go to your chat settings and select “Delete History.” Remember, this only removes messages—you’ll need to delete files and Imagine media separately in their own sections