I cannot give legal advice.  However, generally speaking, credit repair is based all upon the rules of The Fair Credit Repair Act, which is Federal law. As such, the same rules of the FCRA apply for every state. However, if you are asking about specific laws for operating a credit repair business in the state of Maryland, here is some information that may help you:
http://credit-aid.com/states/maryland_credit_repair_laws.htm