The Hawaii Department of Health web site goes into full detail concerning the requirements. Below are the main points...

HOW TO APPLY FOR A MARRIAGE LICENSE

The prospective bride and groom must appear together in person before a marriage license agent to apply for a marriage license. Proxies are not allowed.
The prospective bride and groom should be prepared to provide the necessary proof of age and present any required written consents and approvals. All of the necessary documents should be obtained prior to applying for a marriage license.
The prospective bride and groom must prepare an official application (you can fill most of this out before you get to Hawaii) and file the application in person with the marriage license agent (this must be done on Maui).
Upon approval, a marriage license is issued at the time the application is made.
The marriage license costs $65.00, payable in cash at the time the application is made.
The marriage license is good only in, but is valid throughout, the State of Hawaii.
The marriage license expires 30 days from and including the date of issuance, after which it automatically becomes null and void.Paradise Maui Weddings http://weddings.paradisemaui.com/