For the validity of temporary profession it is required that: 1/ the person who is to make it has completed at least eighteen years of age; 2/ the novitiate has been validly completed; 3/ admission has been given freely by the competent superior with the vote of the council according to the norm of law; 4/ the profession is expressed and made without force, grave fear, or malice; 5/ the profession is received by a legitimate superior personally or through another.
Source: Code of Canon Law (Vatican.va)