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

https://wiki-book.win/index.php/What_Should_I_Do_if_Grok_Delete_All_Doesn%E2%80%99t_Show_on_Mobile%3F

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