How to add a new wireless printer to my MacBook Pro?

Then you will have to enter your Wife's name as listed there and her password that she uses to login to the Mac.

She can also change your Standard User to an Admin user by following these steps:

1. Choose Apple menu > System Preferences.
2. Click Users & Groups.
3. Click the lock icon to unlock it, then enter an administrator name and password.
4. Select a standard user or managed user in the list of users, then select “Allow user to administer this computer.”

She will need to do this after she logs into her account.

Go to  > System Settings > Users & Groups. How many users do you have there and which one is marked Admin?

If you only have one user other than the Guest Account, then that name is the Administrator and the password is what is used to unlock your Mac on startup.