MacBook Air version 12.7.6

so I need to enable screen recording for google, though it requires me to put a username and password to make changes so google can have access. I tried to put in the password that I use to access my Mac book air. Doesn’t work. (Under the lock signal it says to put password to allow this. Didn’t say anything about username, but it does have a little box with for username.) So first time I didn’t try it with the username. Second time I tried with my Apple ID password. Absolutely nothing. So then I was going to put username but then I realized… I don’t know what the username is. So I searched up on google how to find your username for the system preferences and it said to go to users and groups, above admin it said it should have the username, so I checked and it’s blank. So I searched up again how to find the username. Said to go to finder then press Go and then press home. It gave me something in all lowercase. So I put it into the username box by itself and nothing. So then put it into the username and put the MacBook login password into the password box and it didn’t work. I even tried to put it the same way with the Apple ID password and nothing. Absolutely nothing. I don’t know if my username is wrong or if the password is wrong or if both are wrong, or if it’s just the computer. All I know is that I need to have screen recording enabled for an an upcoming exam. Can anyone please help?