Apple ID retrieval and about the passcode

To unlock your iPhone, follow the steps described in the Apple article:

(< iOS 15.2) ->: If you forgot your iPhone passcode

If you forgot your iPhone passcode - Apple Support

(iOS 15.2 or iPadOS 15.2 and newer) If you see an iPhone or iPad unavailable message or Security Lockout screen

If you see an iPhone or iPad unavailable message or Security Lockout screen - Apple Support

An iPhone will disable for 1 minute after six failed passcode attempts in a row. The seventh incorrect passcode attempt will lock you out for 5 minutes, the eighth attempt for 15, and the tenth for an hour.

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Have you forgotten your Apple ID?, Check your Apple ID via your email box, see this Apple article: If you forgot your Apple ID

If you forgot your Apple ID email address or phone number - Apple Support                  

OR see -> Having trouble signing in? -> https://iforgot.apple.com/password/verify/appleid

See also -> If you can't connect or sign in to iCloud

If you can't connect or sign in to iCloud - Apple Support

Have you forgotten your password? -> See this Apple article: If you forgot your Apple ID password

If you forgot your Apple ID password - Apple Support

Then see this Apple article: What to do after you change your Apple ID or password

What to do after you change your Apple ID or password - Apple Support

See also this Apple article: If your Apple ID is locked or disabled -> If your Apple ID is locked or disabled - Apple Support (CA)