The address on the W-2 and the address on your tax return do not have to match. People move all the time.
The W-2 must be on your 2019 tax return if it is for 2019. The address on the W-2 does not matter. People move all the time; that it may have your "old" address is irrelevant. That you do not work there now is irrelevant. If you worked and earned money there in
2019
is what matters. If necessary, phone, email and/or snail mail the old employer to make sure they know where to send your W-2 now.
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.
W-2's come from your employer, and they have until Jan. 31 to issue it. Some employers allow you to import the W-2 through the software, but often you still need information from the actual W-2 just to import it. So waiting for your employer might be your only choice now.
https://ttlc.intuit.com/questions/1934390-how-do-i-import-my-W-2
https://ttlc.intuit.com/questions/2588751-why-can-t-i-import-my-w-2