All marriage license documents are signed with one's current legal name, never the intended new name.
There is no legal requirement for name change after getting married; it is a right a couple may choose to exercise.
Traditionally, the bride has taken the groom's last name. If you are intending anything other than the traditional name change, check with each agency for its requirements to accomplish that. If an agency requires more than a certified copy of your marriage license, see King County District Court, for details on a court-ordered name change.
Washington State law does not impose a time limit after the wedding by which a name change must be accomplished. However, if you are making the change more than a year after your wedding, check with each agency to determine if a certified copy of your marriage license will suffice to change your name with them.
To assume the new last name, you should first obtain certified copies of the marriage certificate. Then work with each agency to change its record of your name. These may include:
Some agencies may accept the red and gold commemorative marriage certificate you receive after the wedding; however, you should expect most agencies to require a certified copy of your marriage record.
The contents of this webpage are not intended as a comprehensive digest on marriage licensing and should not be construed as legal interpretation of the law or advice. If you have any questions or concerns about your legal rights or obligations with regard to marriage, you are encouraged to seek the advice of an attorney.