How do I find a document to show an apartment complex for my GI Bill that shows how much money I have coming in?

eBenefits > My Documents.

I had this same issue. In all actuality there is nothing official that will tell them that you are getting X for BAH. Your apt complex is going to have to allow you to use either a bank statement of an online BAH calculator to prove this; I used a combination of these in addition to proving that I was enrolled in school. Your disability, if you are receiving it, is available in a letter that you can get directly from the ebenefits page.

I would try Ebenefits or show them you are enrolled in school and look up your BAH online.