• 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.

This will enable you to move on to add multiple W-2's and you can complete the steps to .  See the Screenshot below to add another W-2.

If you have already filed your tax return, then you will want to file an amended tax return to add another W-2. First, you will want to wait until your original tax return is processed by the IRS. If you are receiving a refund, you should wait until the check is issued. Amended returns must be filed by mail.

To amend a 2016 return, follow the steps in the article below: https://ttlc.intuit.com/replies/5114064

Edited: 03/14/2017