Qualifications for waitress/barista

Hello everyone, I'm going to korea next year, probably with a H-1 visa I'm actually a waitress in switzerland in a bar/café/restaurant and have experience in that field. I'll start a barista international certification soon. I speak French as a mother language, english as my second language, i also speak german and a very little bit of spanish and I'm learning korean. I'm looking for a job in that field (waitress or barista) What qualifications do I need ? What level of korean do I need to speak ? do I need to take an official test (like TOPIK) ? Any recommendations, things I need to know ?