help with restore a passcode for unlock a note on my device

hi,

i had iPhone 7 till a few days ago and i just upgrade it to iPhone XR.

on my iPhone 7 i had a note that was locked with a passcode and i always unlocked it using the fingerprint technology, and thats why i cant remember it...

when i upgrade my device, the new iPhone XR dont have the fingerprint technology but only the face ID.

when i try to unlock this note, the device asks for a password (which i dont remember) and it also done remember the password by the password key (that opens with the help of the face ID)..

i realy dont know what to do and its very important to me...

please help...?