Form 16 is a certificate issued by employers to employees detailing tax deducted and deposited. It cannot be issued if the Tax Deducted at Source (TDS) is still due. This means the employer must have already deducted and deposited the TDS before issuing the Form 16 to the employee.
Form 16 is basically a certificate provided by the employer to employee stating the amount of tax deducted and deposited with the specified authorities after taking into account the Incomes and specified exemptions and deductions.