Send a message through the desktop USAA site, under the account you want reviewed. They will then respond back by asking you for your current income and any 'other' income you want to add on for consideration. You usually get a response within hours depending on when you submit your USAA message. By the way no documents or pay stubs are needed to be uploaded for this request. Hope you get your credit limit increase! Good luck!
COBrat, you have to go to usaa.com but on desktop setting if you are using your mobile phone or tablet. Then go to messages, then you can select send a message based on account type. If you still cannot find it then call in and they will be happy to help you over the phone to do am account review for a credit limit increase.