Sister's Apple ID password pop-up and apps persist on iPad

I have a sister who recently sync her iphone and my ipad before handing the ipad before me and there’s a pop up saying “please enter your password “ which is my sister email and the appstore, contact, and password app is also sync to her even though i logged out of her account a long time ago and I recently tried everything like closing the continuity option and all the shared information on icloud. I can’t even update my tiktok or instagram without it saying “please enter your password” again its my sister email. How to solve it?