Three years ago, the newly elected Pope Francis unveiled his papal agenda for all the world to see – at least for those who knew where to look.

Francis turned to Twitter, of all places, for the first time on March 19, 2013, the very day he was formally installed as pope. He sent two messages highlighting his concern for the planet, his call to care for the poor and his desire to shift the church away from a posture of judgment.

“Let us keep a place for Christ in our lives, let us care for one another and let us be loving custodians of creation,” he tweeted on the day of his inauguration.

He followed that up with, “True power is service. The Pope must serve all people, especially the poor, the weak, the vulnerable.”

That Pope Francis has confounded and frustrated some in the church isn’t news at this point. The agita for some, especially conservative Catholics, began just a few months into his papacy, during his visit to Rio de Janeiro for World Youth Day.

There, he urged young people to “make of mess” of things in the church. And on his way home, he held a news conference aboard the papal plane during which he responded, “Who am I to judge that person?” when asked about gay Catholics.

It would be the first of many news conferences where Francis would gently, but unmistakably, challenge those who wish the church wouldn’t change.

But as I argue in my book, “The Tweetable Pope,” Francis has been upfront about his desires for reform in the church since his first days in office, when he took to the social media platform to lay out his vision.

It was on Twitter, after all, where he chided gossiping cardinals and bishops who were leaking damaging stories about their theological adversaries during the first part of the contentious synod of bishops in October 2014.

The conversation in Rome had turned to controversial issues such as homosexuality, divorce and shattered families – at the pope’s urging, no less – and opponents of change were intent on derailing the process through gossip and innuendo.

Francis tweeted his frustration. Sure, the pope’s tweets are delivered to about 30 million followers in nine languages, but sometimes the intended audience is a bit smaller.

“Let us ask the Lord for the grace not to speak badly of others,” he tweeted, “not to criticize, not to gossip, but rather to love everyone.”

When the final document of the two-year process is unveiled sometime after Easter, expect portions of it to show up in the pope’s tweets.

In June, when he released the first papal encyclical devoted entirely to protecting creation, Francis again used Twitter to make his point. Perhaps realizing that few Catholics would take the time to read his nearly 200 paragraphs, which included calls to reduce carbon emissions and to close the gap between the rich and poor, Francis lobbed what his spokesman dubbed a “Twitter bomb.”

For 24 hours straight, the pope tweeted key lines and phrases from his encyclical, reaching tens of millions of people — a feat that would have been impossible just a few years ago.

Some point out that the pope isn’t actually tweeting himself, and to some extent, that’s true. The only time a pope has ever hit “tweet” was when Pope Benedict XVI published the first papal tweet in December 2012.

But the small team of advisers who run the @Pontifex account get a papal sign-off for every tweet published from the pope’s account. And the contents usually come from Francis’s speeches and homilies.

Now the pope, and his team, are turning to Instagram, the wildly popular photo-sharing app. Under the account name Franciscus, the pope probably will bring to Instagram the same inspiring, consoling and challenging themes he has tweeted — with more photos.

Just like on Twitter, Pope Francis will approve every post on his Instagram account before it’s posted. And he’s off to a robust start. Earning more than 1,000 followers per minute in the first few hours after launching his account, he became the fastest person to accumulate more than one million Instagram followers in a single day.

Francis has been clear, at least on social media, about where he intends to lead the institution under his care. He’s adopting another platform to spread his message of reform further. Only this time, the revolution will be illustrated.

Michael J. O’Loughlin is a religion journalist and the author of “The Tweetable Pope: A Spiritual Revolution in 140 Characters.”