Most commoners have only a given name (praenomen) and no formalized family name. Many have epitheths (cognomens) based on the location of their home, their work or even personal characteristics, such as Marcel (the) Cooper, Simon from Vosne, or "Mad Dog" Dorian.
Nobles often have several given names, using any or all of them, and additionally have a family name (nomen), usually based on the location of their family's ancestral home or derived from their current holdings. Male Frankish nobles add the prefix "Fiz" or "Fitz" to their father's name to denote "son of..."
A list of typical Frankish names
A list of typical Fraeging names
A list of typical Morath names
Cargan names and structure (external link)