How to show down payment when applying for loan

[Edgar Diaz]

Do I need to prove that the money I have for a down payment came from income reported or can I say that I got it as a private loan? I am going to apply for a mortgage pre approval but I don’t know if I can show the money for the down payment as a loan deposited into my bank account or if it needs to be shown to have come from income reported by myself or my co sponsor