First you need to register your firm either as Sole Proprieter or as Corp or LLC. After getting your company formation certificate you can apply for Sales Tax Permit from here : https://sales-tax-application.com/worksheet/
Important is after getting a Sales Tax Permit you need to choose either you will file your taxes quaterly or yearly. Do not miss it else they will not take minute to suspend your license and file penalities on you.
Infra IT Shop
Just wanted to say the website registered above wanted $188 to register in my state. I also got sketched out when it asked for my personal SSN. I was able to do it on the state government website for free with a bit of research, so it may pay to look around for how to do it directly.