Need to recover 6 digits to access my iphone

You can't "recover" the passcode unless you remember it.

Otherwise, you will need to reset / erase the phone and then set it up again with a new passcode. It might be a good idea to write that down and keep it in a safe place in your desk, even though you are sure that you will never forget it.

If you have a current backup, you can use that to restore the phone.

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