A few notes for Washington State

Both applicants must be 18 years of age or older to apply for a marriage license.
holder If one of applicants is 17 a parent (legal custodian) must be present with the applicant and provides their consent.
holder If one of the applicants is under 17 the age requirement must be waived by a superior court judge of the county in which one of the parties resides.

Although the State law does not specify the age of witnesses, the witnesses are witnessing a civil contract.
holder As such, a witness is deemed "competent" for this purpose usually at the age of 18.
holder If applicants wish to have their children or another party who is under the age of 18 be their bridesmaid or best man, it is recommended they have two other witnesses who are over 18 and who also observed the exchange of vows (marriage) sign the marriage certificates.

License Requirements:
Washington State requires a 3-day waiting period from the date of issue.
There are no circumstances where the 3-day waiting period can be waived.

holder For all wedding ceremonies, the bride and groom must obtain their marriage license at least 4 days in advance from the County Auditor.
holder Washington State requires a 3 day waiting period from date license is issued.
    Locate your County Auditor in Washington.
holder The license is valid for only 60 days from date of issue.
holder The license must be presented to the Officiant prior to the ceremony.
holder This must be signed by:  the Officiate, the couple and the two (2) witnesses.
holder The couple and the two (2) witnesses may sign the license before the ceremony so there is one less item to keep track of after the ceremony.

There is no residency requirement to obtain a Washington State marriage license.
holder However, the marriage ceremony must be performed in Washington State.
holder Under no circumstances can a person apply for a marriage license before a divorce is final.
holder A divorce must be final and filed before applicants can apply for a license.
holder If a divorce is granted, and the paperwork filed on a Tuesday, for example, the couple must wait until Wednesday to file an application.

Washington State law prescribes who may perform a marriage.
holder Under R.C.W. 26.04.050, active and retired justices of the supreme court, judges of the court of appeals, judges of the superior courts, superior court commissioners, any regularly licensed or ordained minister or any priest of any church or religious denomination, and judges of courts of limited jurisdiction may perform marriages.

There is no special form the marriage ceremony must take.
holder The only requirement during the marriage ceremony is that the bride and groom each declare, in the presence of two witnesses and the officiant, that they take each other to be husband and wife.

A marriage ceremony can be on a boat as long as there is a qualified officiant and it must take place in Washington State waters.
holder A ship captain may not perform a marriage ceremony unless qualified as an Officiant under Washington State law.

Proxy marriages (where someone stands in for the other party) are not recognized in Washington State.
holder The two parties must be present before the two witnesses and the officiant in order for the ceremony to be performed.

Washington State marriage license may not be used in another state or country.
holder The ceremony must be performed in Washington State.