1) Spanish people have two surnames.
The first surname is the father's first surname (Sánchez) and the second surname is the mother's first surname (Montes). Well, this was the tradition until a new law was passed and parents can choose on the order of their children's surnames.
That means that now a child may have as his/her first surname that of his/her mother and second that of his/her father.
2) Women have the same surnames all their lives and these do no change with marriage.
You can read the names of the bride's parents on the top left-hand corner: Arnulfo Mejía Zurita and Yolanda Cárdenas Ceja, which means that the bride's name is (and will be after the wedding) Yolanda Mejía Cárdenas. In the same way, the groom's name is Armando Ayala Durán (his mother has two names and two surnames, something quite common).
Some women use their husband's surname and say "señora de + husband's surname" but this is not so common and a bit conservative. In any case, their "official" surnames in every document will be their "maiden" ones.
