Head to https://travel.hawaii.gov/#/ to create an account, enter your travel information and upload your vaccination card. Remember to bring your physical copy of your vaccine card with you. Filling this out prior to your departure will save you a lot of time!
Find up to date travel requirements here: https://www.gohawaii.com/travel-requirements
REAL ID information for our American guests: You must have a REAL ID (drivers license) before October 1st, 2021 to fly. A passport is also a valid ID for flying. If you need more information, check out this website or your state's DOT website. https://www.dhs.gov/real-id