If you’re booking business class or first class flights on Emirates, your choice of seat is available free of charge.
But if you’re booking the lowest economy fares then pre-seating is normally a chargeable extra cost which is not immediately clear.
Members of Emirates Skywards loyalty scheme however, are eligible for free advance “regular” seat assignment, if they have reached “Silver” status. Gold members are eligible for “preferred” seats free-of-charge.
For full details visit the Emirates Page