Formal:
* Il s'appelle... (literally: "It is called...")
* Son nom est... (literally: "Its name is...")
Informal:
* Il s'appelle... (same as the formal option)
* C'est... (literally: "It is...")
Example:
* Formal: Il s'appelle "Le Chat Noir." (Its name is "The Black Cat.")
* Informal: C'est "Le Chat Noir." (It's "The Black Cat.")
You can choose the appropriate phrase based on the situation and your desired level of formality.