When you change jobs within a financial year, you can submit information on salary received and tax deducted at your previous organization to your new employer for the purpose of tax calculation by the later employer.
In case you do not submit your previous employment salary and tax details to your current employer, there can be an under-deduction of your income tax for the year. Please note that you will see the "Prev Emp" tab only if you joined your current organization after April 1st of the current tax year.
Proof Submission for Previous Employment Information
Please submit a tax working sheet or Form 16 from your previous employer.