Maryland Tax - General Section 11-703

      An applicant for a license to engage in the business of an out-of-state vendor or to engage in the business of a retail vendor shall submit an application to the Comptroller:

            (1)      for each place of business in the State where the applicant sells tangible personal property or a taxable service;

            (2)      if the applicant has no fixed place of business and sells from 1 or more vehicles, for each vehicle; or

            (3)      if the applicant has no fixed place of business and does not sell from a vehicle, for the place designated as the address to which notices are to be mailed.