A sales tax exemption certificate is a document presented when a person would normally have to pay sales tax, according to the New York Department of Taxation and Finance. It is required to prove that no tax is due on the sale.
It is the responsibility of the purchaser to present the sales tax exemption certificate, and it is the responsibility of the seller to maintain records of completed certificates. Each state has its own tax exemption certificate, and documentation requirements vary from state to state, according to Marcum Accountants and Advisors. Nonprofits like charitable organizations, religious organizations, government agencies, educational organizations and credit unions can qualify for sales tax exemption certificates, explains the Comptroller of Maryland.