With a 100 percent total disability rating from the VA you get free registration on every plate type, and you can choose any plate design, which will then display the universal wheelchair symbol. You can also choose the Disabled Veteran plate itself.
Submit the MVA Application for Maryland Parking Placards and License Plates, VR-210, with proof of your rating, to the MVA.
Proof of a 100 percent total and permanent disability rating from the VA, and the completed VR-210 application.