Maybe take a look at this: https://www.englishclub.com/english-for-work/hotel.htm

This is a huge topic. Are you working in reception, housekeeping, kitchen or front of house? As a start, use polite phrases and smile. "Sir" and "Ma'am" are polite terms when talking to the guests. Perhaps you could tell us what phrases you already know, or ask a question like "What can I say when [...add your situation here...]?"