I bought a present for/to my mum.
Quien realiza la acción? qué hizo? que compró? a quien o para quién?
me, you, him, her, it, us, you, them
I bought it for my mum
I bought it for her
I bought her a present
I love you te amo / a tí
You love me tu me amás/ a mí
I love him yo lo amo / a él
I love her yo la amo/ a ella
They love us ellos nos aman / a nosotros
We love them nosotros los amamos / a ellos
Show me the bracelet, please. Show it to me, please.
Don´t tell Juan the story. Don´t tell it to him.
You must buy Gabriella the dress. You must buy it to her.
I gave the belt to Wang Li. I gave it to him.
Subject and Object Pronouns
https://agendaweb.org/grammar/pronouns-objects.html
