With the sad passing of Pope Francis on April 21 2025, now we have to wait until a new pope is elected. The process can be very long and unruly but eventually a new pope will be elected, to become the next pope the first step is to be a Catholic Priest for more than 5 years and be over 35 years old, you also need to have a college degree in Catholic Philosophy and a masters in Divinity.
Along with the education you need to be an unmarried man who wishes to stay celibate, and then you can become a Bishop, becoming a bishop is more rare than a priest while there are 400,000 priests worldwide, but only 5000 bishops.
As a Priest the next step is to wait until a bishop over 75 retires or dies and meet the same requirements as a priest plus a PhD in Theology, and once you have that your name is given to the Apostolic Nuncio and he picks out a priest and does background research to determine if they can be anointed by the Bishops in The Vatican City. After the Bishops vote you on your name is sent to the current Pope where he decides if you can be a Bishop.
Once you finally become a Bishop after a couple of years you can become a Cardinal, Cardinals are simply Bishops with fancier outfits, names and other bigger responsibilities, the biggest one being voting on the newest pope. The only way to become a cardinal is to wait for the pope to appoint you as one and of the 5000 Bishops only 200 are ever Cardinals.
Now you’re a Cardinal you must wait for the current pope to die or retire and then all the cardinals are bought to The Vatican, where they are isolated in every way to the outside world.
Next step is based on whatever the pope said he wanted his replacement to be, but typically the instructions are 4 times a day go to the Sistine Chapel to vote, to become pope one cardinal must get ⅔’s votes by other cardinals, This process is typically why it takes so long it can last however long they need to decide on 1 new pope. Your final step is to pick your new name when you become pope, you would normally choose a name of a previous pope.