3. could you introduce yourself. is more appropriate. 

1 and 2 would not be used in English; it sounds like the verbs "introduce" and "tell" or "share" are being confused. As Ikki said, #3 could work. For example, at the beginning of a small class or Bible study with unfamiliar people, the leader may ask of each person: "Could you please introduce yourself?" Most people would say their name along with their grade level, college major, or reason for taking the class (depending on the context). If only your name is needed, then the leader could just say, "Please tell us your name," but that would not be a warm and friendly way to begin as a class. I hope this helps. Peace.