Form 16 is a TDS (Tax Deducted at Source) certificate issued by an employer to an employee as proof of TDS deduction from the employee's salary income. It is issued under Section 203 of the Income Tax Act, 1961. Form 16 is a TDS (Tax Deducted at Source) certificate issued by an employer to an employee as proof of TDS deduction from the employee's salary income. It is issued under Section 203 of the Income Tax Act, 1961.