As previously mentioned, the VA doesn't lend any money but relies on mortgage companies to actually make the loans.
The VA's role is to provide a guaranty. Think of the guaranty as an insurance policy for the lender. The guaranty means the lender is protected against loss if you or a later owner fails to repay the loan. The guaranty replaces the protection the lender typically receives by requiring a down payment.
The VA loan guaranty is typically 25 percent of the loan amount.