What's the difference between a "Resale license" and a State Tax ID number?

Your Sales and Use tax number is utilitized for what you are calling a resale license. The form is really called a Sales and Use Tax Resale Certificate. You issue these to the vendor for goods purchased for resale- this allows the vendor to not charge sales tax to your company. you can go to the Texas website and download the form. Business Licenses are obtained from local (city) government and you do need one.