Md. Code, Election Law § 13–222

(a) (1) By the next deadline for filing a campaign finance report after receiving a contribution specified in paragraph (2) of this subsection, a treasurer shall issue a campaign contribution receipt on the form that the State Board prescribes.

(2) A campaign contribution receipt shall be mailed or delivered to each person who makes one or more contributions in the cumulative amount of $51 or more.

(3) At the request of a contributor, a treasurer shall issue a campaign contribution receipt for any other contribution.

(4) A campaign contribution receipt issued under this section is evidence of the contribution.

(b) The information from a campaign contribution receipt shall be included in the campaign finance report filed by the treasurer under this title.