In Washington State any person over eighteen years of age can choose and use any name he or she wishes as long as the purpose of the change in the name is not to defraud another. For example, it is not legal to change names to avoid creditors or to escape obligations such as child support. Changing names is legal and relatively easy to accomplish.
Special provisions apply for changing a child's name.
Each of these categories are discussed below. Use of the husband's surname at marriage is a matter of custom, not law. If you wish to use your new husband's name at marriage, simply sign all documents except the marriage license using his last name. If you wish to retain your name rather than to adopt your new husband's name, sign the marriage license and related documents using your own name. No other action is needed because your name is not being changed, but is staying the same despite a contrary custom.