Help me please…completely forgotten…
Then you will have to do a factory reset using recovery. In case you dont synch all data within your Google account you should be able to usw #twrpwoflashing to connect to a PC and save some date. The factory reset will wipe your phone completely
If you’ve been using full-standard “Google” then the pwd is likely your Gmail password.
Sorry, then completely no change
Worst case = factory reset
If your data partition is not encrypted you can have a look at this topic:
This way you can avoid a factory reset.