The Michigan Certificate of Mailing is a document issued by the United States Postal Service (USPS) that verifies that a piece of mail or package has been sent to a recipient. It provides proof that the item was mailed and the date it was sent. There are two types of Michigan Certificate of Mailing: Domestic and International. The Domestic Certificate of Mailing certifies that mail within the United States was sent on a certain date. It also provides a tracking number for the mail. The International Certificate of Mailing certifies that mail outside the United States was sent on a certain date. It also provides a tracking number in some cases. Both types of Michigan Certificate of Mailing can be obtained at the USPS post office or online.