Business resale certificates vary by state, but typically include identifying information of the reseller, the reseller's tax exemption or use number, description of items being resold and a signed statement that the items are being purchased for resale. Resellers should consult the state tax codes where they do business.
A resale certificate allows a business to purchase goods from another business without paying sales tax. It is assumed that they are going to resell those goods and collecting sales tax when they do.
Businesses usually need to apply for a tax exemption or use tax license to use a resale certificate. They should do this with the state tax department. In order to qualify, they need to be licensed to do business in that state.