From the Secretary of State's Website:
Welcome to Rapid Renewal!
This online service makes it possible for you to renew your motor vehicle registration and to pay your local excise tax in one simple transaction.
You should receive your new registration certificate and decals within 7 business days. If your registration will expire within 7 days, and you are planning to travel out-of-state with your vehicle, you may wish to renew your registration in person at your municipal office or the Bureau of Motor Vehicles. Who Can Use This Service?
Registrations for both passenger and commercial vehicles can be renewed online. However, "for-hire", island use, emergency/coach, buses, vehicles over 12,000 pounds GVW, apportioned, special mobile equipment, tractors, municipal and state vehicles must be renewed in person.
To use this service, you will need:
Payments may be made by Electronic Check.