تَعَلَّمَ — he learned: the person acquires knowledge.
عَلَّمَ — he taught: the person imparts knowledge to someone else.
وَعَلَّمَهُ — and he taught it; وَ means “and,” and ـهُ refers to the Qur’an.
For example, Zaynab learns a recitation rule correctly from a teacher and later helps her younger sister practice that rule. The first action illustrates تَعَلَّمَ; the second illustrates عَلَّمَ.
Both verbs share the root ع ل م, but their verbal forms express acquiring knowledge versus teaching it to others.