The Washington Declaration of Mailing (WDM) is a legal document that is used in Washington State to provide proof of mailing. It is an affidavit, which is signed and notarized, that verifies the sender has mailed a specific document or package to a recipient on a certain date. The Declaration is used to establish that due diligence was taken in attempting to notify a recipient of a document or package. The Washington Declaration is used in many scenarios, including when a legal notification needs to be sent to a party in a lawsuit or other legal matter. It is also used when a party needs to provide proof of mailing for an insurance or loan application. There are two types of Washington Declaration of Mailing: regular and certified. Regular Washington Declaration of Mailing is used when the recipient's signature is not necessary. Certified Washington Declaration of Mailing is used when the recipient's signature is required.