Nos mandó escribir una redacción para las vacaciones.

English Translation

He gave us an essay to write during the vacation.

para should be por - otherwise it means “before the vacation”

This is a reasonable use of para to describe a deadline. It doesn’t have to be an incredibly specific date. For example tenemos que comprar comida para la próxima semana could mean that we need to buy food for next week in general, we need to buy food before next week, or perhaps the proceeding sentence is la fiesta es el sábado which means we have until the end of next week to buy food.