There is no legal requirement for either party in a marriage to change their name once married. If you do decide to change your name, there is no centralized process or agency that will change or update your name for all agencies. To assume a new last name, you must contact each agency individually.
You may consider changing or updating your name with:
Most agencies require a certified copy of the Department of Health (DOH) Certificate of Marriage. If you received your marriage license from Snohomish County, you can order certified copies from Snohomish County Recording.
If an agency requires more than a certified copy of your DOH Certificate of Marriage, visit the Snohomish County District Court website for more information on the court-ordered name change process.