Chances are if you come to Korea for work or travel (and are 18+ ㅋㅋ), you will be invited to go out and drink with your coworkers or friends. When you go out with your coworkers, it is called a “회식” and you eat, talk, and drink with each other.
Now if you don’t drink, don’t be afraid to refrain from drinking and just tell them the reason why. Aside from the older generation, most people will have no problem.