iPhone locked. Requires passcode. Unable to enter with double tap

Probably you may have entered the wrong passcode multiple times. After 10 failed attempts the iPhone will get disabled.

Following this process is the only way out if your iPhone is disabled. The steps given in this link will help you reset the passcode -> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

There are two passcodes; Lock Screen Passcode and Screen Time Passcode.

Following this process is the only way out to reset both passcodes. The steps given in this link will help you do that -> If you forgot the passcode for your iPhone, iPad, or iPod touch, or your ...

Note: If you restore from a backup then the Screen Time Passcode will be back on your device.

1. Force restart the iPhone / iPad --> Force restart iPhone - Apple Support
2. iPhone restarts> Enter Lock Screen Passcode --> Click-> If you forgot the Lock Screen Passcode for your iPhone, iPad, or iPod touch, or your ...
3. Then go to Settings -> Accessibility -> Guided Access and change the passcode