¿Cómo 'se' llama usted? Why se??
como 'se' llama usted? this means what is your name. but why 'se' is used?Can't we use 'es' instead of 'se'? because 'es' is translated as 'is' in english then why 'se' is used?
5 Answers
"¿Cómo se llama?" literally translates "What do you call yourself?" You could also say "¿Cómo te llamas?" to be a little less formal.
An English speaker might also be tempted to ask "¿Cuál es su (tu) nombre?", literally translating to "What is your name?". About the only time someone is likely to use that expression is when filling out a form or something.
¿Cómo SE llama? is almost the same as ¿Cömo TE llamaS?. The first one is used with more respect, like when asking an adult you don't know, your boss, teacher, etc. To ask the question to younger people you use the second one.
Spanish people like me put "se" instead of "es" because it sounds horrible in Spanish to pronounce "¿Cómo es llama usted?" It sounds horrible, and the meaning in Spanish doesn't have sense. If we put "¿Cómo es llama usted?" in a test, the teacher would give less points in the test because we had written the word like poop. That's why we write "¿Cómo se llama usted?" instead of the sentence literally translated from English to Spanish that would be the sentence I mentioned many times: "¿Cómo es llama usted?" The most Spanish people (like me) know how to speak English and some ask: "Why we have to write like this in English if in Spanish it is very different?" But they know that no all the languages translate literally the same. OK? Bye bye butterflies. XD
As I understand the question that was asked, it was:
"Why is 'se' used in "¿Cómo se llama?"
I put it to you that the correct grammatical answer is because the sentence "¿Cómo se llama?" involves the use of the pronominal reflexive verb "llamarse" which means, among other things"to be called, to be named, to name oneself".
As with all reflexive verbs, when the verb is conjugated, the clitic "se" at the end of the verb is transferred to a place in front of the conjugated portion of the verb.
There is more detail about reflexive verbs on our Reference Page, Here ----> Reflexive Verbs
Cómo se llama?"
I think this best said as "What is it called" If so it is a passive structure.
I may be wrong (Maybe I am wrong) for Heidita. 
