Securing a mortgage is one of the most important steps in the home buying process. The last thing everyone wants is to have a mortgage fall through at the most inoportune time.
It is highly reccomended that buyers obtain a Firm Pre-Approval at the earliest oportunity in the buying process.
Lenders want to make sure that buyers can afford the monthly payments and that they have sufficient down payment available. As a buyer you will also need to pass the new "stress test" which will show the bank that you will be able to afford monthly payments should a mortgage rate increase happen.
Lenders want to know how much money buyers have coming in every month, how long have they been receiving such payments for and how secure is the monthly income for the forseable future. They may ask to see pay stubs, T4s, Notices of assesments, bank statements, etc for at least the past 6 months.
They will also want to know how much money you have saved up for your down payment and where is that money coming from. Personal savings are typically the ideal source of down payment funds although gifts from immediate family may also be accepted. Funds that are received from family and friends that have to be paid back are typically not accepted as valid sources of down payment.