Indiana Vendor Information/TIN Certification is a process that Indiana businesses must complete in order to become an approved vendor for the state. The process requires businesses to submit their Taxpayer Identification Number (TIN) to the Indiana Department of Revenue, along with financial information such as company name, address, and contact information, in order to be certified as an Indiana vendor. There are two types of Indiana Vendor Information/TIN Certification: Form ST-105 and Form ST-200. Form ST-105 is used to register businesses with the state and obtain a TIN, while Form ST-200 is used to certify businesses as an Indiana vendor. Both forms must be completed and submitted to the Indiana Department of Revenue in order to become an approved vendor.