Depends on a few things. If it's to a group of people, and whether or not someone has preceded the introduction with one for you. One person to another, a cold introduction with no lead-up: "Hi, I'd like to introduce myself. My name is Marlana [Williams] and..." (continue with some reason you are introducing yourself) "...I have been a writer for radio and print for twenty-five years." / "...I was told you were the point of contact regarding information about the exhibit." Sometimes if the person doesn't expect you to approach them, make sure you also add: "May I have a moment of your time?" One person introduces you to another person, you would then say: "Pleased to meet you." / "Nice to meet you." You are in a group, and need to address a group of people: "Hello, everyone. My name is Marlana [Williams]." Sometimes follow with a pleasantry such as: "Welcome to the fifth annual Kakawin Indigenous Art gala." You are in a group, and have been introduced, and now it's your turn to reply: "Thank you, for that introduction, and thank you all for attending/coming. It is my pleasure to be here."

Depends what type of formal setting...

Greetings everyone , my name is Sandra.