1. Obtain a seller's permit: In most states, you must first register for a seller's permit (also called a sales tax license) with the state's tax authority. This permit allows your business to collect sales tax from customers and issue resale certificates to suppliers.
2. Issue the certificate: You present a valid resale certificate to a vendor or supplier when purchasing items for resale. The certificate informs the supplier that they do not need to charge sales tax on the transaction.
3. Collect tax from the end customer: When you sell the item to a consumer, you are then responsible for collecting the sales tax from them and remitting it to the state.
4. Use for inventory only: The certificate can only be used for items you plan to resell. Using it for items for your business's own use, such as office supplies, is illegal and can result in penalties. 

Key differences: Reseller certificate vs. seller's permit

While often confused, a reseller certificate and a seller's permit have distinct purposes.

Seller's permit: A license that gives a business the legal authority to collect sales tax from its customers.

Reseller certificate: A document that allows a business to make tax-exempt purchases of inventory from its suppliers. Multi-state variations

State-specific certificates: Many states require their own specific resale certificate form.

Multi-state certificates: Some states accept a multi-jurisdiction form, such as the Multistate Tax Commission's Uniform Sales & Use Tax Certificate, which can ease compliance for businesses operating across state lines.

Non-accepting states: Some states will not accept out-of-state resale certificates, so businesses may need to register for a sales tax permit in that specific state.