My name, Daniel Fox, and its variants Dan Fox and Danny Fox, are quite common in English speaking countries.
My parents named me Daniel J. F. Fox, and this is how I have always signed my papers and will continue to sign my papers. Upon acquiring Spanish nationality my legal name in Spain changed to Daniel J. Fox Hornig and this is how my name appears on the UPM’s website and in official documents emitted in Spain. By Spanish law a Spanish citizen must have two surnames, one inherited from each parent, and current administrative practice also permits no more than two names (this explains the vanished F.). Although this naming practice is more gender equitable than that most common (but by no means unique) in the United States, morally my name continues to be that which my parents chose for me.
In my case, Fox is probably an English translation of Fuks or Fuchs, although little is known about the origins of the family of my paternal grandfather, from whom the surname originates.