Kakao Talk
One of the two mobile applications that get the highest use in South Korea is called Kakao Talk. Newcomers to the country will want to have the app downloaded as quickly as they can so that they can communicate with their classmates or workplace.
Kakao Talk, just like other social messaging systems (such as WhatsApp or Messenger), offers a function called Channels that enables users to connect with a variety of brands and be notified of their promotions (most likely sent in Korean).
Both the Play Store and the App Store have Kakao Talk accessible for download. You could also wish to install the application on your personal computer or Mac in order to have everything you need in a single location while you are working.
Website: https://www.kakaocorp.com/page/service/service/KakaoTalk?lang=en
Download iOS: https://apps.apple.com/us/app/kakaotalk/id362057947
Download Android: https://play.google.com/store/apps/details?id=com.kakao.talk&hl=en_US