"He did not want it."
Translation:Él no lo quiso.
The verb form "quiso" tells you that the subject is either "him", "her", or "it" (or formal "you). That information is often enough to get the point across without explicitly mentioning the subject. In a sentence like this one, unless there was a particular reason to emphasize "he" (like to distinguish him from a woman he's standing next to), the "él" would normally be omitted.