Md. Code, Insurance § 6–113

A declaration or report that must be filed under this subtitle complies with the filing requirement if the declaration or report is:

(1) mailed and postmarked by the United States Postal Service on or before the filing date;

(2) delivered on or before the filing date to a private delivery service recognized by the Commissioner, if the delivery is evidenced by a receipt; or

(3) sent by electronic means in accordance with § 2–116 of this article.