State tax filing

What credit are you trying to take?    When you go through the Maryland state return, you will come to a screen titled Take a look at Maryland credits.   Most of the credits in on 502CR are entered from that page.   If you are asking about a different credit, one that is not listed, please ask.    Credits you have taken and can edit are listed up top and unused credits are listed.  Click Start next to the credit you need to take.