"Julia wants salad."
Translation:जूलिया को सलाद चाहिए।
It's just the way they form that construction. Instead of using a verb, "to want," and then conjugating it appropriately for Julia ("Julia wants..."), one uses "cāhīe" ("is wanted/needed"). To specify TO WHOM something "is wanted," you mark that person with "ko."
सलाद चाहिए could exist by itself. "Salad is wanted/needed." But if the context does not tell us to/by whom salad is needed, you have to say "BY/TO JULIA salad is wanted."