I’m doing my taxes joint with my wife and I’m in the military. It’s asking about the SP wages but, I’m not sure where to find it or what it is.

The question is about your spouse's wages.  That would be found on her form W2 from her job. 

To take advantage of the military tax breaks in the "My Info" section both you and your spouse should select your "home of record" as the resident state.  The advantage is you would both then fall under that state's tax laws and not need to file in other states.  Some states even exclude military pay from taxation if you are resident but due to military orders are stationed out of state. 

Here is a page that has links to the state publications concerning military taxpayers and their spouses.