How to unlock your iPhone if you forget your password

If you have forgotten your Apple ID Password......

If you forgot your Apple ID password - Apple Support

Or, are you asking about the Passcode? It is usually a 6 digit phrase.

If your iPhone is running iOS 15.2 or higher........you can use the instructions linked just below:

How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support

If your iPhone is not running iOS 15.2 or higher........please use the instructions linked below, but note that you must use a PC or Mac.

If you forgot your iPhone passcode - Apple Support

If you have a backup of the phone, you can use the backup to restore the data on the phone during the new setup.