Open Settings on your iPhone or iPad and tap your name at the top
Open System Settings on your Mac and click your name or Apple Account
Open the App Store and check the account shown at the bottom or in account settings
Open the Apple Music, Apple TV, or iTunes app and look at the signed-in account
Go to appleid.apple.com and sign in if needed to see your Apple ID
Check your email inbox for Apple receipts or Apple notifications that show your Apple ID email
Look in Messages for sign-in or purchase confirmations from Apple
Ask a family member if you are part of Family Sharing and use the same Apple ID email
Check saved passwords in iCloud Keychain or your password manager for Apple account details
Use the Find My app and view the account currently signed in
If you forgot it, use Apple’s account recovery or password reset page to find the Apple ID email