You can do it in many environments, but will need to provide the loan officer with 3 years of income tax statements, 3 recent pay stubs, bank statements, etc., which all need to be verified in order to get a FULL PRE-APPROVAL.
Do not settle for a pre-qual; they are somewhat meaningless. A full pre-approval will make you almost as good as a cash buyer.
There are several people I recommend, each one in a different lending situation, bank, mortgage bank, mortgage broker, mortgage banker/broker.
The application process should NOT cost you anything (if someone is charging you, run!), and you can interview several before making a decision.
As a real estate broker, I advise my agents not to work with anyone who does not have a pre-approval or help them get one first.
I have trained Realtors for many years and teach the course at Stony Brook University. If you would like some guidance, feel free to give me a call and I will be happy to discuss the entire process with you (no fees, no obligations...just education) 631-425-6150.