Resetting 6 digit password

What your iPhone is asking you to input is your passcode that setup prior to setting up Face ID. If you do not remember the passcode then you will need restore your iPhone as new to reset it. Here is how-->>If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

Good Luck.

Axel F.

If FaceID is disabled and you don't remember the passcode and you do not have a backup, data loss is inevitable. See here: https://support.apple.com/en-us/HT204306