Mich. Comp. Laws § 168.768
The board of election inspectors shall verify that there is an elector's signature on the absent voter ballot return envelope and that the statement on the absent voter ballot return envelope that the ballot is approved for tabulation is complete. If the elector's signature is missing or the statement that the absent voter ballot is approved for tabulation is incomplete, the board of election inspectors must immediately contact the city or township clerk. If the elector's signature is present and the statement that the absent voter ballot is approved for tabulation is complete, the board of election inspectors shall open the absent voter ballot return envelope, take out the ballot, and, without unfolding the ballot, compare the ballot number on the ballot stub with the ballot number on the face of the absent voter ballot return envelope. If the ballot numbers match, the board of election inspectors shall detach the perforated numbered stub and prepare the ballot for tabulation, as directed by the secretary of state. Each ballot must be inserted into the tabulator. One of the election inspectors shall enter the elector in the poll book as having cast an absent voter ballot.
MCL 168.768