Anonymous grading hides student identities while you grade, helping to eliminate bias. When enabled, you see students identified by numbers or codes instead of names.
Toggle anonymous grading in the Deliver tab before the test begins. This applies to all graders and hides student names during grading
Once enabled teachers would not be able to disable the feature from their end for that test, if needed it has to be done by the administrator.
Also the export to PDF features will be disabled if anonymous grading is enabled