The pre-approval letter plays an important part in the home buying process. This is an unofficial letter from the mortgage lender that lets agents and sellers know the amount of money a buyer can borrow in order to buy a house. Many sellers will require that a buyer show this pre-approval letter before that seller will accept any offer. This provides an important protection for sellers as they can avoid doing business with buyers who do not have the ability to get the money to buy the home. The pre-approval letter does not constitute an official mortgage approval from the lender. The buyer will still have to go through the entire loan process before he or she can actually get the money. In some cases, mortgage lenders will deny people after they have been granted a pre-approval letter, but it is more common for the bank to adjust the amount of money it is willing to lend.