she -> they
her -> them
he -> they
him -> them
it -> they
Hers/His/Its -> theirs
Hers -> theirs
His -> theirs
Its -> theirs
Voici un lien qui peut t'aider à mieux comprendre les pronoms personnels et les pronoms possessifs :
https://www.anglaisfacile.com/exercices/exercice-anglais-2/exercice-anglais-27632.php
N'hésite pas si tu as des questions.