I agree, starting with local then state licensing boards are the first steps.
Your state may have very helpful resources that will illustrate the
requirements. Since you are selling a product online, I would also educate
yourself on internet sales tax rules and regulations as one size does not fit
all anymore...good luck!

Hi, Check out this section of our site for information about business licenses and permits. Here's some additional information about online businesses as well.

You will need to register your business name with your state or county agency
that handles such matters. You will also want to establish a business bank
account.

Business licenses are issued by cities and counties, not by states. Some
cities license all business activities; others license only select
activities. A quick call to your city clerk's office can tell you whether you
need a license.

If your state collects sales tax, you will need to collect it on sales of
your product, so you will need a sales tax permit.

It'll depend on the state where you operate. But surely you'll need a
business license. In the state of Washington, for example, you'd need a
master business license.

Observation: Often times the business licensing process also gets you on the
"tax rolls" for things like sales taxes.