Hawaii Certificate of Authorization to Fabricate/Repair Application (COA) is an application for a business to become authorized to fabricate or repair products in the state of Hawaii. The application is filed with the Department of Taxation in Hawaii and requires submission of an application fee and supporting documentation. Depending on the type of product and business, different forms and materials may be required. The COA is divided into two types of applications: Fabrication Certificate of Authorization and Repair Certificate of Authorization. The Fabrication Certificate of Authorization is for businesses that want to fabricate or manufacture products in Hawaii. The Repair Certificate of Authorization is for businesses that want to repair or service products in Hawaii. Both types of applications require submission of a fee, application form, and supporting documentation. Once approved, the business will be granted a Certificate of Authorization from the Department of Taxation. This certificate will be valid for one year and must be renewed annually. The COA is necessary for businesses to remain in compliance with the rules and regulations set by the Department of Taxation.