I forgot my 6 digit iPhone 13 passcode

A forgotten passcode cannot be recovered. It requires you connect your iPhone to your home computer and erase the device using iTunes (Windows) or Finder (Mac), after which, assuming you have been regularly backing up your iPhone, you can restore the from from backup.

See this link for directions --> If you forgot your iPhone passcode - Apple Support

The only way around a forgotten passcode is to factory restore the device. Or with the 13 iOS 15 now it should be giving you an option to erase the device which wipes out the passcode.