Here is some info that might be of help to you:
Daughters of Charity of St. Vincent de Paul (Paulists)
In 1840, Mary appeared to Sister Justine Bisqueyburu (a Seminary Sister of the Daughters of Charity) in Paris, France and commended the Green Scapular to her. It's known as "the Scapular of Conversion," and its promises are the strengthening of faith, protection against Satan, a happy death for Catholics, and, most of all, for conversion for those outside the Church. It's to be worn or carried by the faithful, or given to an unbeliever for their conversion. The following prayer is to be said daily by the wearer:
Immaculate Heart of Mary, pray for us now and at the hour of our death
Cor immaculatum Mariae, ora pro nobis nunc et in hora mortis nostrae
If the scapular is given to an unbeliever for their conversion, the person giving the scapular prays the prayer for them if the unbeliever does not want to pray the prayer himself. If the unbeliever does not want the scapular, it may be hidden in their vicinity and the prayers said for him. Enrollment in a Confraternity is not necessary for this scapular, but the scapular should be blessed by a priest before use.
Ten years after the manifestation of the Miraculous Medal to Sister Catherine Labouré in 1830, the Blessed Mother entrusted the Green Scapular of the Immaculate Heart to Sister Justine Bisqueyburu, likewise a Daughter of Charity of St. Vincent de Paul.
The manner of using the Scapular was indicated by the Blessed Virgin. Since it is not the badge of a confraternity but simply a double image attached to a single piece of cloth and suspended from a cord, investiture is not required. It suffices that it be blessed by a priest and worn by one for whom it is intended. It may be placed in the clothing, on the bed, or simply in the room.
You can receive a free green scapular here (although a donation is appreciated):
How do I obtain Green Scapulars or send in prayer requests for the Society newsletter?
To request prayers especially for a person or intention, send in all appropriate information. People do not need to be members to request prayers or be prayed for. For Green Scapulars, request as many as you need. We ask only that you use all of them and not keep them unused in a purse or a drawer. Some send an offering to offset costs or help the work of the Society. Others send a thanksgiving donation instead, after obtaining their request. While donations are always appreciated they are never necessary.