In general, the documentation you will need includes:
Property Information (if you already have a contract on a house)
Purchase Agreement.
If you are selling your current home, copy of listing contract.
Income & Assets
Pay stubs for the last 30 days.
For the past two years:
Names and addresses of each employer.
W-2s
Statements for each bank, mutual fund, and/or investment account for the last two months.
Explanation and source for deposit.
If large deposit was a gift:
Signed gift letter (lender can supply).
Copy of gift check.
Copy of deposit receipt.
If you own more than 25% of a business:
Corporate or partnership tax returns.
If self-employed:
Tax returns for the last two years (with schedules).
If you own rental property:
Tax returns for the last two years and current rental agreements. If taxes and insurance are not escrowed we will need tax bills and insurance information for these properties.
If you are retired:
Pension Award Letter.
If you receive Social Security:
Social Security Award Letter.
If you are counting child support as income:
Copy of divorce settlement.
Copy of twelve months of cancelled child support checks.
Debts
Explanation of credit report anomalies, including:
Late payments, credit inquiries in the last 90 days, charge-offs, collections, judgments and/or liens.
Bankruptcy filed within last seven years (bring a copy of your bankruptcy papers).
VA Loans
Copy of DD Form 214, Report of Separation.
Miscellaneous
Photo ID and proof of Social Security number.
Residence addresses for the past two years.
If applicable, a copy of your divorce decree.
If you are not a citizen, a copy of the front and back of your green card.