You can use the free resources on score.org and sba.gov to get a pretty good idea of the steps to take to set up a new business. But nothing beats having your own expert give you professional advice in their area of expertise.
Please consult with your CPA or attorney about the best strategy for your business. They are best suited to help you pick between sole proprietorship, LLC, S-corp, or some other legal structure.
Mine told me years ago that I didn’t need a business license as I’m commissioned to do what I’m doing. On that basis, I’ve never had a license.
As my credit union does not offer business accounts and I don’t want to go back to a bank, I don’t have a business checking account.
Now that I have had time to think about all the stuff I’ve done under my business name, I think I probably did need a license and at least an S-corp and an EIN in that name.
I’ve come to think that my CPA and attorney likely did not understand what being an NSA involves, as it’s partly notary and partly signing agent (which is freelance clerical work). If you do any of the inspections or I-9 or fingerprint work that notaries get asked to do, that’s even further from the scope of just notary work.
So, it’s probably a good idea to set up a legal structure and get a license and EIN for your business before you get too far along. Just consult an attorney or a CPA on the best way to go there, as they are the experts. Random notaries on Facebook or other social media can offer opinions. They can not provide expert guidance — only an attorney or CPA can.