This is the 431st most frequent Portuguese word.
escreveu
"Escreveu" means "wrote."
In this context, 'escreveu' is the verb 'escrever' conjugated in the third-person singular past tense to indicate an action performed by 'Ela' (her).
Ela escreveu uma carta para a avó dela.
She wrote a letter to her grandmother.
Here, 'escreveu' is used in an interrogative sentence to ask about the author of a story in past tense.
Quem escreveu essa maravilhosa história de aventuras?
Who wrote this wonderful adventure story?
'Escreveu' is used here to describe how someone performed the action of writing in the past, emphasizing the manner of the act.