Which phrase to use when answering como se llama usted?

The correct phrase to use when answering "¿Cómo se llama usted?" (How are you called? - formal) is:

"Me llamo [your name]" (My name is [your name]).

For example:

* ¿Cómo se llama usted?

* Me llamo Juan. (My name is Juan.)

Important Note: "Usted" is the formal way to address someone in Spanish. If you are speaking to someone you know well, you can use the informal "tú" and answer with:

* "Me llamo [your name]" (My name is [your name]).

* "Soy [your name]" (I am [your name]).

Remember, the choice between "usted" and "tú" depends on the level of formality and your relationship with the person you are speaking to.