I just read a story about a California State Senator changing her part affiliation. She is latina and was shown with a hyphenated last name. Well, that isn’t the way it works here.
Let’s take an example. Carlos Castro and Maria Garcia have a daughter. They name her Marta Luisa. Her “full name” is Marta Luisa Garcia Castro. No hyphen. And, in all the places I know of she can legally use Any assortment of her names (for example, Luisa Castro or Marta Garcia) where her “full name” is not required.
So, where did hyphenated names come from? As best I can tell it is a result of computer systems that only allow a single “last name”. In Latin America I see forms that allow two apellidos (last names). Official documents such as driver’s licenses and passports will show both last names.