"My name is Julia."
Translation:मेरा नाम जूलिया है।
So is it mera and not meri because it is referring to name and not Julia?
Because मेरा नाम acts as a third-person pronoun. हूँ is only used with a subject that is a first-person (singular) (pro)noun. It works the same way in English; we say "My name is..." and not "My name am..."