From the same employer? Is the second one marked Corrected? Or why did you get 2?
The amending instructions link is below. However, keep in mind that current year amendments will not be able to be processed until Form 1040X is available. Currently, it is tentatively scheduled to be released on 02/24/22.
How to Amend a Tax Return - - 2021 will be added to this list once the form is ready.
If your tax return gets rejected or you have not filed yet, you can add or replace the W-2 and then file. But if it has already been accepted, you will need to amend it later.
Do the two W-2s have different amounts on them? Employers often send multiple W-2s if they run out of room in certain boxes, usually Boxes 12 & 14 or the state & local tax boxes. If so, you only enter one W-2 containing all the entries in Boxes 12 & 14 (or state & local taxes) from all your W-2s.
If you really do need to amend (i.e., your employer legitimately sent a separate and/or corrected W-2), Form 1040X (amended return) won't be available in TurboTax Online till around February 24. (See https://care-cdn.prodsupportsite.a.intuit.com/forms-availability/turbotax_fed_online_individual.html for updates on Federal form availability.) You should wait for the IRS to process your original return AND for TurboTax to start accepting amended returns.
Yes they are from the same employer, I got two of them because I got promoted within the year. So I have to add it in the first tax return I filed