If you have multiple W-2's, you can import each one individually.
- On the Income and Expenses tab, you can click Add/Edit next to the W-2 section.
- You can then add another W-2, by clicking the option Add a W-2 for.
This will enable you to move on to add multiple W-2's and you can complete the importing steps below.
https://ttlc.intuit.com/replies/3389204
If you have already filed and your return has been accepted, you will need to file an amended tax return to add an additional W-2. The amended return will need to be filed by mail.