I don’t remember my password to iCloud

(< iOS 15.2) See this Apple article: If you forgot your iPhone passcode

If you forgot your iPhone passcode - Apple Support

(iOS 15.2 and newer) How to reset your iPhone, iPad, or iPod touch when you forgot your passcode

How to remove your iPhone, iPad, or iPod touch passcode without a computer - Apple Support

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

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

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

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