Formal:
* お名前は？ (O-namae wa?) - This is the most polite and formal way to ask someone's name. It literally means "What is your name?"
* お名前を伺えますか？ (O-namae o ukagae masu ka?) - This is another very polite way to ask someone's name, which translates to "May I ask your name?"
Informal:
* 名前は？ (Namae wa?) - This is a more casual way to ask someone's name.
* なんて言うの？ (Nante iu no?) - This is a very informal way to ask someone's name, literally meaning "What do you call yourself?"
You can also use the following phrase to introduce yourself and ask for their name:
* 私は[your name]です。 あなたの名前は何ですか？ (Watashi wa [your name] desu. Anata no namae wa nan desu ka?) - This translates to "My name is [your name]. What is your name?"
Here are some other important things to keep in mind:
* Always use honorifics when speaking to someone older or of higher social status.
* When someone tells you their name, you can reply with "どうぞよろしく (Douzo yoroshiku)" which means "Nice to meet you."
Remember that practice makes perfect. The more you use these phrases, the more comfortable you will become with asking someone's name in Japanese.