During the Jubilee Year of Mercy there are special opportunities to obtain a plenary indulgence. What does this mean?

God always forgives us. Through the Sacrament of Penance our sins are forgiven. God’s forgiveness eliminates our eternal punishment, but that doesn’t mean that our sins haven’t taken a toll on our souls. Our souls may need a bit of work, which the Church teaches us takes place through temporal punishment in Purgatory: “All who die in God's grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven.” (CCC #1030)

“An indulgence is the remission before God of temporal punishment for sins whose guilt is already forgiven, which a properly disposed member of the Christian faithful gains under certain and defined conditions by the assistance of the Church which as minister of redemption dispenses and applies authoritatively the treasury of the satisfactions of Christ and the saints.” (Code of Canon Law, 992)

So how do you receive an indulgence? During this Jubilee Year of Mercy one way is to perform a Corporal or Spiritual Work of Mercy with a few additional qualifications:
1) Make a profession of faith (the Apostles’ or Nicene Creed) during a period either 20 days before or after performing a work of mercy;
2) Receive Communion and meditate upon mercy for each work of mercy performed in order to receive an indulgence;
3) Participate in the Sacrament of Penance during a period either 20 days before or after performing a work of mercy.

The Church makes no claims about the amount of time in Purgatory remitted, mostly because this time does not conform to our human sense of time and space. And, if you are recalling from Church history concerns about indulgences being abused, here is more information about reforms impacting indulgences. Bottom line: Our sincere efforts to please God will be rewarded.