Storing sales tax rates in the database

colleagues! I am developing a program to record sales and generate financial documents in the United States. And I have to take into account the tax rates for different territories in my program. I read an article from Wikipedia and another article. I have not met the US tax system before. Recognized that there are special methods of taxation and that the purpose of the special taxation method can be considered even as a street or separate product. And I have some questions:

Are there common ways to implement databases to store this information or some examples? Maybe there is a manual or a book.

How often do tax information change? I have found some services that provide tax information via the Web API, but they are all paid and the prices often depend on the number of requests. Maybe there is a free way?

I also learned that to get a list of territorial tax rates, I had to use the address and possibly a zip code. Is there a unified way to store an address structure in the database?

I would be very grateful to answer my general and rather vague questions. English is not my first language, I'm sorry for the mistakes.