There are many reasons why as a borrower, you would want to apply for a mortgage. The most obvious is that you cannot afford to buy the house in cash and need to make installment payments on it over the next 15 to 30 years.
Adjustable loans have their downsides too. One major downside is that you will still have to make higher payments if the rate adjusts, even if you pay down the loan.
You might have heard the terms conventional mortgage or conforming mortgage. These terms refer to mortgages that lenders can issue, then package up and sell to another company.
For those lenders to sell them to a secondary market for the best rate, they must conform to Freddie Mac or Fannie Mae standards, such as your loan percentage of the overall home value.