A mortgage Lender can analyze your income, debts, and cost of the home to produce a conditional qualification letter. The letter tells you what they can lend and any conditions that apply. Your letter accompanies your offer to the seller to verify your qualification.
You must make the effort for a written application with all documentation. Your lender can speak highly of your credentials when the selling agent calls to find out about you.
A conditional qualification letter is the highest standard for your approval. This compares to a pre-approval letter where the lenders review might be as little as a credit check and phone interview.