That gives him full and unhindered power over the entire Catholic Church and makes him an important source of authority for the world’s roughly 1.4 billion Catholics.
The Pope does not receive a salary, but all his travel costs and living expenses are paid for by the Vatican.
A papal funeral has traditionally been an elaborate affair, but Pope Francis recently approved plans to make the whole procedure less complex.
Previous pontiffs were buried in three nested coffins made of cypress, lead and oak. Pope Francis has opted for a simple wooden coffin lined with zinc.
He has also scrapped the tradition of placing the Pope’s body on a raised platform – known as a catafalque – in St Peter’s Basilica for public viewing.
Instead, mourners will be invited to pay their respects while his body remains inside the coffin, with the lid removed.
Francis will also be the first Pope in more than a century to be buried outside the Vatican.
He will be laid to rest in the Basilica of St Mary Major, one of four major papal basilicas in Rome.
A basilica is a church which has been granted special significance and privileges by the Vatican. The major basilicas have a particular connection to the Pope.
Who chooses the new Pope?
The new Pope has to be chosen by the Catholic Church’s most senior officials, known as the College of Cardinals.
All men, they are appointed directly by the Pope, and are usually ordained bishops.
There are currently 252 Catholic cardinals, 138 of whom are eligible to vote for the new Pope.
The others are over the age of 80, which means they cannot take part in the election, although they can join in the debate over who should be selected.
How is the Pope chosen and what is the conclave?
When the Pope dies (or resigns, as in the rare case of Pope Benedict XVI in 2013), the cardinals are summoned to a meeting at the Vatican, followed by the conclave, as the election is known.
During the time between the Pope’s death and the election of his successor, the College of Cardinals governs the Church.
The election is held in strict secrecy inside the Sistine Chapel, famously painted by Michelangelo.
Individual cardinals vote for their preferred candidate until a winner is determined, a process which can take several days. In previous centuries, voting has gone on for weeks or months. Some cardinals have even died during conclaves.
The only clue about how the election is proceeding is the smoke that emerges twice a day from burning the cardinals’ ballot papers. Black signals failure. The traditional white smoke means the new Pope has been chosen.
How is the decision about the new Pope made public?
After the white smoke goes up, the new Pope normally appears within an hour on the balcony overlooking St Peter’s Square.
The senior cardinal participating in the conclave will announce the decision with the words “Habemus Papam” – Latin for “we have a Pope”.
He will then introduce the new Pope by his chosen papal name, which may or may not be his original given name.
For example, Pope Francis was born Jorge Mario Bergoglio, but he chose a different name for his papacy in honour of St Francis of Assisi.
Who can become the Pope?
In theory, any Roman Catholic man who has been baptised can be considered for election to become Pope.
In practice, however, the cardinals prefer to select one of their own.
When the Argentine-born Pope Francis was chosen at the previous conclave in 2013, he became the first pontiff ever to hail from South America, a region that accounts for roughly 28% of the world’s Catholics.
But historical precedent suggests the cardinals are far more likely to pick a European – and especially an Italian.
Of the 266 popes chosen to date, 217 have been from Italy.
BBC