What does a maintenance vendor need to be approved by a property management company?

Four things, all current: a certificate of insurance naming the management company and the property as additional insured, proof of active workers compensation, a W-9, and a registration in the company's credentialing platform (Compliance Depot, NetVendor or RealPage Vendor Credentialing are the common ones). L&J Projects keeps all four current and issues the COI within 24 hours, so the first work order is not delayed by paperwork.