Spell The Name Zach
Whatever is on the birth certificate is the correct spelling for that person as for nickname it depends on how the parents decide to spell it or the person with the nickname to decide.
Spell the name zach. Zechariah also transliterated as zachariah and zacharias is a theophoric masculine given name of persian and hebrew origin meaning god remembers. You can use the alternate name speller to get unique spellings for common names. That is why we display the most common spelling of the name.
Maybe you just want to put a unique spin on a common name. Zack and variant spellings zach zac zak zakk is sometimes a given name but more often it is a hypocorism or short form of another given name usually zachary in the english speaking world which derives from zechariah. Alternate name speller here are different ways to spell zack.
I would say the correct way to spell zach is zach there are different ways that people spell the name zach zack zak zac ect. It comes from the hebrew word zakhar meaning to remember and yah one of the names of the god. Do you love this name but want a different spelling.
Though zechariah is the original transliteration of the name and used in the english translation of the book of zechariah zachariah spelled with the letter a instead of the letter e is more popular with a common diminutive being zach.