Like most people, you will probably wait until submitting a purchase contract on a home before applying for a mortgage. By then, not only will you know the specific property you want, but also how much you need to borrow. At that point, the lender will require that you fill out a loan application and reveal specific information about your current and past financial situations.
The following checklist is a good place to start for gathering the information you will need:
Original purchase contract (the loan officer will make a copy and return the original to you)
Copy of earnest money (deposit) cancelled check
Employment history details
Last two years' W-2 forms
Last two years' income tax returns
Paycheck stubs for past 30 days
Verification of secondary income (for example, investment accounts, bonuses, a part-time job, child support or social security income)
Assets: Account numbers, balances and branch addresses
Stocks/bonds (current market values)
Debts: Account numbers and addresses
Explanation of any credit problems (for example, previously declared bankruptcy, excessive credit card debt)
Divorce or separation documents (if you receive or pay alimony or child support)
Landlord's name and phone number (if renting)
Disposition of present home (if you already have a home, do you plan to sell it or rent it out?...