Hey Hecmir,
You will need some form of proof of funds. How were you planning to fund the purchase? Conventional loan, cash in the bank, hard money? I suspect you need to figure out and arrange proof of funds. For cash its bank statements. For conventional loan its approval letter.
Not 100% sure what you need with hard money. I suspect you will bees to share the details of the deal to obtain approval for funding with the hard money lender.
Hope this helps.
Harsh