Why should I enter my SSN instead of my ITIN on the Wages (Form W-2) screen?

An ITIN doesn't authorize someone to work in the United States, so your W-2 shouldn't show your ITIN in Box A. It should show your Social Security number (SSN) that's valid for employment. If your ITIN is shown in Box A, you should contact your employer to get a corrected W-2 that shows your SSN in Box A.