A mortgage preapproval letter shows a lender's initial willingness to lend based on a preliminary review of your finances, typically lasting 30 to 90 days. It indicates seriousness to sellers and helps determine your budget but is not a loan guarantee. Preapproval can expire early if financial conditions change, requiring reapplication. The process takes hours to days, involving income, credit, and document verification. Multiple preapprovals are allowed to compare offers.

