Does Pope Francis write the books ascribed to him, or are they ghostwritten? A number of books have been published with Pope Francis as the author, such as The Joy of the Gospel: Evangelii Gaudium in 2013 and Praise Be To You – Laudato Si'; On Care for Our Common Home in 2015. Are these books actually written by the man himself, or are they ghostwritten by others?
Pope Francis' first encyclical Lumen Fidei was co-written by Pope Benedict XVI

That’s one of the reasons why it is particularly striking that, in the Year of Faith, we have an encyclical on faith written, as Pope Francis said, by “four hands” — his and Benedict XVI’s — and fittingly signed on the feast of St. Peter. The didactic duet and distinguished date suggest that Lumen Fidei (The Light of Faith) is less the act of a particular pope and more the faithful exercise of the Petrine office in apostolic succession.
NCRegister - The World Needs Lumen Fidei

His second encyclical Laudatio Si is indubitably his brain-child

I do not want to write this Encyclical without turning to that attractive and compelling figure, whose name I took as my guide and inspiration when I was elected Bishop of Rome. I believe that Saint Francis is the example par excellence of care for the vulnerable and of an integral ecology lived out joyfully and authentically

Its frame is the Canticle of the Sun and full of personal references
Evangelii Gaudium might be an exception, it is very long and very well researched and probably similar to a bill passed through Congress where the bills author gets all the credit, but it takes a team to come up with it.

Most of the other works with Pope Francis' name on them are compilations of interviews or addresses though, like St. John Paul II with Crossing the Threshold of Hope
For example On the Family is one of Pope Francis books and the synopsis says:

Throughout his addresses, the Holy Father especially emphasizes the primary role of God and faith in family life, and the crucial importance of regular family prayer to draw on God's grace for strength, love, joy and unity within the home.

and The Strength of Vocation

Pope Francis' new book &quot;The strength of vocation. Consecrated life today.&quot;, coming out on December 3rd, is fruit of a four-hour long conversation between the Holy Father and Spanish Missionary Fernando Prado, tackling themes such as vocation, consecrated life and the struggles the Church is facing today.
&quot;The strength of vocation&quot;: A book-length interview with Pope Francis

So he's got considerably less work to do in producing a book that is just off-the-cuff remarks.