A license to make a living as a professional photographer does not necessarily come in the form of an official document. For many long-time photographers, their photography license is metaphorical, obtained by building and maintaining a good reputation for quality work. In nearly all cases, your "license to work" is your exemplary photography.
However, it's good for professional photographers who work full-time or operate a photography business on the side to obtain a license for tax purposes. Here's how to get what you need to launch your photography business.
Enroll in a photography school to obtain a degree in the craft or take photography classes to establish and sharpen your photography skills. Going to school for photography can only help you, as it allows you to build a portfolio of photographs and gain valuable experience.
Go to your town clerk's office and obtain a license to operate a business. Ask the clerk for the license form and fill out the necessary information to obtain a tax identification number for the purpose of filing taxes for your photography business.
Begin to build your photography business by word of mouth. Set up a website where you can post examples of your work and list an email address and phone number where people can contact you.
If you specialize in a specific type of photography, register with an association or organization of those photographers. Membership in these groups is often only bestowed to those with exceptional talent, reputation and experience.
Getting an academic degree in photography isn't necessary, but it can certainly help jump-start your photography business. This accreditation can also help if you're just starting out and need to prove your photography chops despite a meager portfolio.
If you're posting photos to a website, make sure your photographs are copyrighted to prevent others from stealing your work. While your photographs are in essence automatically copyrighted because you produced them, filing for a copyright can only help you in the event someone tries to steal your work and pass it off as their own.