Washington Proof of Service is a legal way to serve someone with a court filing or another legal document. In Washington State, there are three main types of service: personal service, substituted service, and constructive service. Personal service requires a process server to attempt to personally hand the documents to the other party. If the party refuses to accept the documents, the process server can leave them at the party’s home or place of business. Substituted service involves leaving documents with an adult at the party's residence or place of work, and then sending a copy of the documents by registered or certified mail. Constructive service requires an affidavit to be posted in a public place, such as a courthouse, and then a copy of the documents sent by registered or certified mail. Proof of service is provided by the process server after the documents have been served. It is a document that details the date, time, and location of the service, the name of the recipient, and the type of service used.