Can't remember which email you used to sign up? If you used Apple's "Hide My Email" feature when creating your account, here's how to find it:
Open the Settings app.
Tap your name at the top to go to your Apple ID settings.
Tap iCloud.
Tap Hide My Email.
You will see a list of your private relay email addresses and the apps they are associated with.
"Hide My Email" is a privacy feature on iOS devices. You can read more about the feature on Apple's website: https://support.apple.com/en-us/105078
