If you’re selling through a stand-alone store and have determined that you have nexus with a state, the next step is to register for a sales tax permit with that state to begin collecting sales tax. Once you have a sales tax permit (or seller permit), you can start collecting sales tax in your store.
If you're collecting sales tax, we recommend submitting a resale certificate separately for each applicable state, or using the MTC form to apply for exemptions in multiple states at once—so that orders shipped to those states are automatically exempt from sales tax in Printful Enterprise.
For more information on setting up sales tax on Shopify, check out their Help Center.