If you are filing your Hawaii state return by mail then you should include a copy of your W2 and other Income forms. Make sure that you have signed your return and send it with some form of tracking or signature receipt so that you can know when they have gotten it.
Mailing addresses:
Type of Return- All Districts (Hawaii Department of Taxation)
Net Income Tax without payment
P.O. Box 3559
Honolulu, HI 96811-3559
Net Income Tax with payment
P.O. Box 1530
Honolulu, HI 96806-1530
