Small businesses have to have a number of business licenses and permits in order to operate and most are tax-deductible expenses. In the simplest case, a business may just have to have a basic license to operate. In the most complicated case, a business may have to have some sort of complex permit, such as an environmental permit, to operate.
The type of regulations, licenses, and permits vary widely based on federal, state, local, and industry requirements and laws.
Go to Business.gov's site and based on your zip code, you can find the licenses and permits you need for your business. Then, the next best thing to do is consult with a tax accountant to be sure you take advantage of every deduction due to you.