Selling while still owning money to bank

[Kenton C.]

Hi guys,

I am new to investing in real estate, and plan on buying a duplex or SFH for buy and hold, taking out a 30 year loan (also paying it over 30 years), and putting down 20% downpayment to start.

If for some reason, I want to exit the market I am investing in, or are forced to sell, what happens to the loan, and money I owe the bank? Am I paid upfront by a buyer, then repay the loan back to the bank with that money? What if the buyer also takes out a loan? 

Please help clear up some confusion I have about this process. Thanks!