To manufacture a trailer, you must get approval from your state's Department of Motor Vehicles or Transportation, as operating without a license is an offense punishable by high fees and the shutdown of your business. Don't forget that you may have to apply for other licenses, depending on what you intend to do with the trailers you manufacture. Requirements vary by state, but most procedures and required documentation are the same no matter where you're located.
Obtain the application from your state's DMV -- many post the application on their websites. It will be called an automobile/trailer manufacturer license, and may be coupled with a distributor license. Fill it out with your business information, including the name of your business, your tax identification number and the names of the other people who are applying with you.
Describe the trailers you're planning to manufacture. Include the line-make, or brand, but not the model or year, unless the application specifically requests that information.
Fill in the questions about your criminal background, if any. You won't be stopped from getting the license in most cases, but the resulting background check can make the licensing process take longer.
Answer questions about your business, including the type of company you're applying on behalf of, and any partners or subsidiaries. If required, indicate the amount of the business that each person listed owns, and make sure the resulting total is 100.
Read the application to find out what type of documentation is required by the state. You may have to include a dealer list, financial statement, a description of your building and employee roster, an experience background statement on each of the owners or a franchise agreement, in addition to other documents required by the state.
Prepare the fee. Some states allow you to submit a credit card slip in lieu of a check. Make sure everything is made out to the proper department. Fees can be anywhere from $50 to several hundred dollars.
Send the application, documentation and fee to the address listed on the application. Your approval should come in the mail.
Most manufacturer licenses are also distributor licenses, but you aren't required to select both parts of the license when you fill it out if you won't be engaging in both activities.
The Environmental Protection Agency in your state may require additional licenses, depending on your business operations and location. Contact them before starting to manufacture trailers to be sure you're meeting all regulations.
A manufacturing license does not allow you to sell trailers directly to consumers.