My iPhone 15 keeps asking for my password for an email address I haven't had for 9 years.
The email address that my phone shows that is for a phone I had years ago and that is not my current email address.
[Edited by Moderator]
iPad Air 2, iPadOS 15
if you're updating an app, delete the app and redownload because the app must of been transferred from phone to phone going way back - hence being attached to an old email.