In the beginning, you owe more interest, because your loan balance is still high. So most of your monthly payment goes to pay the interest, and a little bit goes to paying off the principal. Over time, as you pay down the principal, you owe less interest each month, because your loan balance is lower. So, more of your monthly payment goes to paying down the principal. Near the end of the loan, you owe much less interest, and most of your payment goes to pay off the last of the principal. This process is known as amortization.
In some cases, you may not be required to provide all of that information. Some loans are referred to as low doc or no doc because they don't require you to prove any of the statements that you make to your underwriter. These loans are normally more expensive, but can be easier to obtain. Additionally, you can obtain a preauthorization before you submit an offer on a home you would like to buy. That can speed up the process, and also shows the seller that you are serious about the purchase.
The programs vary in what they can offer. In some cases direct financial assistance may be provided to help you pay your mortgage for a short period of time. Payment plans or reduced monthly payments may be offered. However most of the government programs and non-profit organizations will help facilitate some form of loan modification to qualified homeowners. This will provide families time to get back on track by ideally lowering their monthly payment, reducing interest rates or waiving fees.