What are the requirements for a valid legal affidavit, to testimony or certifying statement is true and correct?

Common requirements to be admitted in court.

Maryland

Hi,
Here is a link with forms, for all states.
The one I chose was VA, just to see if it would fit your needs.
At the bottom, you can choose Maryland.
http://www.ilrg.com/forms/affidavit-gen/us/va

Best wishes.

A couple witnesses including a notary pretty much covers it, doesn't it?