Form 16 is a TDS certificate issued by an employer to his employee when TDS is deducted by the employer. The employer deducts this tax on behalf of the Government and after deducting deposits the tax to the Government. The employer is then required to give a certificate to the employee giving the details of tax deducted. This certificate is called the Form No. 16 or just Form 16.
If no TDS has been deducted then, the employer may not a Form 16.