In most UK universities, the Master of Arts is a free-standing graduate degree awarded by examination. In Oxford (as in Cambridge), and following longstanding tradition, the status of Master of Arts is a mark of seniority within the University which may be conferred twenty-one terms after matriculation.
If you have completed a BA you will be eligible to take an MA in or after the 21st term since you matriculated (i.e. seven years after matriculation). This is not an automatic process and to obtain your MA you must apply to graduate at a degree ceremony (either in person or in absentia). You must have had your BA conferred in order to take your MA. They can be conferred at the same ceremony provided that sufficient time has elapsed since you matriculated.
You are not at any point eligible to take an MA if your undergraduate degree is an Oxford integrated Masters degree. The Oxford MA is about reaching a new status within the University and not an upgrade of your BA or an additional qualification. It therefore has no subject or class. There is an MA degree fee of £50.00 payable to Lincoln College.
If you would like to make arrangements to have your MA conferred, please contact the Rector's PA, Sally Lacey, on 01865 279804 or firstname.lastname@example.org.