Pope Francis left written guidelines for how he wanted his tomb to be. This is what was revealed in his spiritual testament, which was made public after his death. He himself signed it at Casa Santa Marta on June 29, 2022.
The Pope wanted his tomb to be as austere and simple as possible. He asked that it be in the ground, without decoration, and that it bear a single inscription reading "Franciscus."
As he himself stated, he did not want to be buried in the Vatican grottoes, but in Saint Mary Major, specifically very close to the Pauline Chapel.
The reason is his great devotion to the Salus Populi Romani, Our Lady Protector of Rome. He regularly went there to pray as a cardinal, and as pope, he always stopped by before and after each of his pastoral visits outside the Vatican.
As soon as he left the hospital, he went to leave flowers at the Basilica. It was also one of his last public outings while he continued his recovery, as prescribed by his doctors.
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