One last name or two? Maternal surname or paternal surname? Which first? Depending on where he or she is born, the laws of that country will establish the surname(s) that the boy or girl will bear and in what order.
In 2017, in Spain, the father's surname ceased to prevail over that of the mother after the reform of the Civil Registry. From that moment, the parents must agree on the order of the surnames when registering a newborn child, although if this does not happen, and after a period of three days, it will be the person in charge of the Civil Registry who Establish said order in the best interest of the minor, but not by setting that of the father by default.
Since 2000, newborn babies in Spain can be registered with the mother's last name first if that is what both parents had decided, but in case of not expressly requesting it or if there was no agreement, the last name of the dad.
In most Spanish-speaking countries, each person usually has two surnames derived from the family of their father and mother, in this order (paternal and maternal surnames, respectively). So in the Hispanic tradition we call ourselves with: first name (one or more), paternal surname and maternal surname.
Danni Büchner is invited to Sam Dylan's Halloween party. But the "Goodbye Germany" emigrant has no desire for many other party guests. And find clear words.