When you scan a stack of paper tests — or add a student by hand — that result starts out on its own, not yet tied to anyone's account. You can now connect it to the right student in just a couple of clicks.
Open the options menu (⋯) next to a student in the results view and choose "Link to student account". Search for the student by name or email address, pick them, and the result is connected to their account.
From then on it behaves just like a test taken online while signed in: the name comes from the student's account and stays in sync automatically, so you no longer have to worry about a typo or a name the scanner didn't read quite right.