From the Handbook of Indulgences
Visiting a Church or an Oratory on All Souls Day
A plenary (“full”) indulgence, which is applicable only to the souls in Purgatory is granted to the Christian faithful who devoutly visit a church or an oratory on (November 2nd,) All Souls Day.
Requirements for Obtaining a Plenary Indulgence on All Souls Day (Nov. 2nd)
-Visit a church and pray for souls in Purgatory
-Say one “Our Father” and the “Creed” in the visit to the church
-Say one “Our Father” and one “Hail Mary” for the Holy Father’s intentions
-Worthily receive Holy Communion (ideally on the same day if you can get to Mass)
-Make a sacramental confession within a week of All Souls Day
-For a plenary indulgence be free from all attachment to sin, even venial sin (otherwise, the indulgence is partial, not plenary, “full”).