mange manger mangent
what is the difference
Well, as far as I understand, manger is infinitive (to eat), mange is a form which is used in 1st and 3rd person singular (je mange, il/elle mange), and mangent is 3rd person plural (ils/elles manent). To sum up: grammar is the difference. Hope it will help you.
In french verbs change their endings to correspond to the subject (who is doing the action) and the tense (past, present, future etc.). It’s called conjugation. This might help. https://www.vatefaireconjuguer.com/search?verb=Manger