Indulgences are offered by the Catholic Church as a way to reduce the amount of time believers spend in purgatory after they confess and have been absolved of their sins.
In the Middle Ages, indulgences received a bad reputation because church officials sold them for large sums of money.
Now they can be had through Twitter, Britain's The Guardian reported Tuesday. But it won't be simple, said Archbishop Claudio Maria Celli, head of the pontifical council for social communication.
"You can't obtain indulgences like getting a coffee from a vending machine," he told Italian daily Corriere della Sera.
Pope Francis wanted to offer indulgences to those who attended the Rio de Janeiro event, but realized it would be difficult for some to make the trip, The Guardian said. So he determined that those who followed the events actively on Twitter could be granted indulgences as well.
"But you must be following the events live. It is not as if you can get an indulgence by chatting on the Internet," Celli said.
Catholics wanting an indulgence must have previously confessed and must be "truly penitent and contrite," the church said.
The pope has some 7 million followers on Twitter.