How do I retrieve an old password same iCloud account but just can’t remember the password I used back when I got my account it will not let me in

How do I retrieve an old password same iCloud account but just can’t remember the password I used back when I got my account it will not let me in Because I can’t remember the password how do I get this password I can’t remember it I’ve had so many it’s been back 2017 when I said this account up and I’m trying to give my phone away to someone and it just won’t do.