Mass. Gen. Laws ch. 54 § 94
The city or town clerk or a person designated by him shall open each envelope purporting to contain an official absent voting ballot as soon as possible after receiving it, in the view of any persons who may be present. He shall remove therefrom the inner envelope provided for in clause (c) of the first paragraph of section eighty-seven and, without opening such inner envelope, compare the signature thereon with the signature on the application therefor, except if a family member signed the application or if the voter received assistance in signing the application or the envelope, and examine the affidavit on each such envelope. If he finds that such affidavit has been improperly executed, or does not sufficiently indicate that the ballot was marked and mailed or delivered as required by sections ninety-two and ninety-three, or except as provided in the preceding sentence was not signed by the person who signed the application therefor, he shall mark across the face thereof "Rejected as defective", and shall place on the absent voting disposition list required by section ninety-one or section ninety-one A, as the case may be, opposite the name of the voter the capital letter R. Each envelope, so marked, all applications for absent voter ballots and all lists referred to in this section shall be preserved and destroyed in the manner provided by law for the retention, preservation or destruction of official ballots. If he does not mark the envelope "Rejected as defective", he shall mark a check against the name of the voter on the absent voting disposition list required by section ninety-one or section ninety-one A, as the case may be. Said clerk, or such person, shall record on tally sheets prepared and furnished by the state secretary all envelopes, as well as accepted or rejected ballots of absent voters; and, in cities and towns divided into voting precincts, a separate record shall be made for each precinct.
Said clerk shall notify, as soon as possible, each voter whose ballot was rejected that such ballot has been rejected. Said notice shall be on a form prescribed by the state secretary and provided by the clerk. Unless the clerk determines that there is clearly insufficient time for the voter to return another ballot, the clerk shall then proceed as if the voter had requested a substitute ballot under section eighty-nine. If the clerk received the original ballot by mail, the clerk shall enclose the substitute ballot and other papers described in section eighty-seven with the mailed notice of rejection. If the original ballot was delivered to the voter in the office of the clerk or at a health care facility, the clerk shall attempt to communicate to the voter as soon as possible that the substitute ballot is available. If the clerk timely receives an inner envelope purporting to contain such a substitute ballot, and does not mark it "Rejected as Defective" under this section, he shall strike the letter R from any list on which it has been placed under the preceding paragraph.
Mass. Gen. Laws ch. 54, § 94