Formal:
* Bonjour, je m'appelle Scarlet. (This is the most common and polite way to introduce yourself.)
Informal:
* Salut, je m'appelle Scarlet. (This is a more casual greeting.)
Even more informal:
* Coucou, je m'appelle Scarlet. (This is a very informal and friendly greeting, usually used with friends or family.)
You could also say:
* Je suis Scarlet. (This literally translates to "I am Scarlet" and is a shorter way to introduce yourself, but it can sound a bit abrupt.)
Remember to adjust your greeting based on the situation and the person you are talking to.