Masters' licenses are granted by the Board of Electrical Examiners in Little Rock. You should be able to get the paperwork on line.
Once you submit the paperwork, they will review it and vote on it at their next monthly meeting - then let you know what they want.
The Board is completely separate from an entirely different group that issues contractors' licenses- though having a Masters' is a prerequisite for getting a contractors' license.
I did smile when I saw my license was issued by Charlie Daniels.