Washington Motion To Serve By Mail is a legal procedure that allows a party to a civil case to serve another party by mailing a copy of the documents instead of in-person service. This procedure is available in the state of Washington and is an alternative to personal service or service by the sheriff. There are two types of Washington Motion To Serve By Mail: (1) Mailing with a Return Receipt Requested and (2) Mailing without a Return Receipt Requested. For the first type of service, the document must be mailed by certified mail, return receipt requested, to the last known address of the party to be served. The return receipt is proof of service. For the second type of service, the document must be mailed by regular mail to the last known address of the party to be served. This type of service is less reliable than the first type since there is no proof of service.