In response to Plato:
Only a priest or deacon may bless a scapular. However, any priest, deacon or person authorized to act in the name of the Order, may enrol others in the Scapular. There are some members of the laity and Religious that have been given authority to act in the name of the Order and to enrol others, but only after the scapular itself has been blessed by a priest or deacon.
Blessings! Polishman