If it is a formal situation then you would say: "Good morning/Good afternoon/Good evening. My name is Davis , I'm from China" and then hold out your hand to shake the other person's hand. Say:" Pleased to meet you." and smile at them. The following site has a person say aloud the words or sentence that you have typed in. Choose the accent that you like after you type in your word/sentence. http://www.oddcast.com/home/demos/tts/tts_example.php?sitepal

Hello! My name is Davis and I'm from China (you can include the city as well if you like). It's nice to meet you! (Or you can say, it's a pleasure to meet you. Depending on how fancy you want to sound.)