What’s the type of tax credit you can get for switching jobs in 2019?

There is not any kind of credit for changing jobs.  But.....

Every 2019 W-2 that you received must be reported on your 2019 tax return, even if they are for small amounts.  Remember that each one of those W-2’s has your Social Security number on it, and that income was reported to the IRS by the employer.  You do not want to get in trouble with the IRS for under-reporting your income.

ALL of your W-2’s must be entered on the SAME tax return.  After you enter the first one, you click Add Another W-2.

I wonder if you are thinking about the amount that may have been withheld for Social Security if you had two different employers in 2019.  If the total amount withheld in 2019 (in box 4 of your W-2's) exceeds

$8239.80  the excess amount is included in your refund.