Delete search box from websites

Hello I’m trying to figure out how to delete what I’m guessing is autofill of some kind. When I go to sites like Amazon or even other smaller websites and it has a search function built in to the site it always gives me options to put in things I have searched for before. I know and have deleted my browsing history. But it’s not really something with the browser. It seems to be maybe my phone saving them can anyone tell me where it how I delete those. I also get this from time to time when entering an email in to a log in some sites suggest one of my emails while others do not. Any help would be greatly appreciated thank you very much.