Formal:
* Как вас зовут? (Kak vas zovut?) - This is the most formal way to ask someone's name.
* Как ваше имя? (Kak vashe imya?) - Another formal option, although it is not as commonly used as the first one.
Informal:
* Как тебя зовут? (Kak tebya zovut?) - This is a more casual and informal way to ask someone's name. You would use this with friends, family, or people you know well.
* Какое у тебя имя? (Kakoye u tebya imya?) - This is another informal option, also suitable for close relationships.
Note: The word "зовут" (zovut) means "call" or "name". The form "тебя" (tebya) is used for the familiar "you" (like "you" would be used to address a friend), while "вас" (vas) is the formal "you".
Remember to adjust the formality of your greeting depending on the situation and your relationship with the person you are speaking to.