When imagining the afterlife, it can be tempting to think of purgatory as a specific “place” or “location,” where all the souls are sent before entering into Heaven.
However, the Catholic Church teaches that purgatory is not a “place,” but more of a “process.”
St. John Paul II gave a catechesis on purgatory during a general audience in 1999, explaining what the Church teaches regarding purgatory.
Purification must be complete, and indeed this is precisely what is meant by the Church’s teaching on purgatory. The term does not indicate a place, but a condition of existence. Those who, after death, exist in a state of purification, are already in the love of Christ who removes from them the remnants of imperfection
The Catechism of the Catholic Church is also careful not to label purgatory as a “place,” but speaks only in terms of the process.
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.
The Church gives the name Purgatory to this final purification of the elect.CCC 1030-1031
Purgatory, while it may seem like a place where souls go to, is much more complex, though we will never know fully what it is like until we experience it ourselves.