The loan application process is the pits. If you don't have everything right on your application for a home loan, then you have to repackage and resubmit. Again and again you have to submit if you keep missing little details. It can be mind-numbing and disheartening, not to mention a huge waste of time.
There is a list of items that you NEED to have in order to properly submit your application. All your ducks must be in a row in order for this process to go smoothly. And these items slightly vary depending on the loan you are applying for. But for most loans you need a lot of the same items to the same specifications and accuracy.
The home loan approval process will go nowhere without this. If you are self-employed or make more than 1/4 of your income via commission, then you must submit your federal tax return for review as well.
Next are asset and credit items. Banks statements for past 2 months, stock statements, anything that can be considered a financial asset, even gifts from family and employers. Credit lines are also a needed listing when applying for a home loan. Even the smallest line of credit must be listed. Late payments, charge-offs, etc must be there. They may not disqualify you at all from receiving the loan, but failure to list them will definitely get you nowhere fast. Little things like child support receipts are something a lot of people miss.
To quickly go over specifics per loan type, FHA loans need copy of social security card and your driver's license if you have one and a VA loan requires a copy of your DD214 Forms. Make sure you have everything on that list, go over each document requirement with your broker, banker, or loan officer and then submit your application.