Form 16 includes Part A and Part B
If employer provides only Part A (i.e. TDS certificate) and doesn't provide Part B details so it will be correct or Employee should request the employer to provide Part B details too.
Employer is obliged to provide Part B too. However, if you think that you may not get the same within 31st July (for filing ITR) and if you know all the information of part B, you may file the return using your data.