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

https://noon-wiki.win/index.php/Does_Deleting_on_Grok.com_Also_Delete_Chats_in_the_Grok_App%3F

To delete your Grok chat history on grok.com/app and X, go to your chat settings and choose clear history. Remember this moves items to Recently Deleted, where they stay for 30 days before final removal