TAN registration is necessary for anyone responsible to Tax Deduction at Source (TDS) and Tax Collection at Source (TCS). Furthermore, it is required for issuing TDS certificate and remittance of TDS payments. It is usually business entities that make payments regarding salaries, excessive rents, etc. who are responsible for deducting tax at source. Once the deduction is complete, a TDS certificate will be issued by the business entity registered for TAN as proof of tax collection.