Form 16 has details of the tax deducted and the branch of the bank where it is deposited into the central government account. For example, if a TDS of Rs 2,000 was deduced from your April salary, form 16 will have its gives.
Form 16 is the final certificate issued by your employer giving details of the salary you have earned and the tax deducted on your behalf and paid to the government.
It is given at the end of the financial year, generally by April 30. If there has been no TDS on your salary, you just get a salary certificate and not the Form 16.