Are all of St. Paul’s letters really written by him??

Question:  Are all of St. Paul’s letters really written by him?  Someone told me that some may have been speeches or other people’s materials?

Today, if someone writes a piece of literature and attributes it to
someone else, that’s considered a fraud. In biblical, times, however, it
was both common and acceptable to write something that you believed
captured the essence of someone else’s thinking and then attribute its
authorship to that very person, even if he or she was no longer alive.
We know through Scripture scholarship, that many of the books of the
Bible, including the Gospels, were not written per se by the person
whose name appears in the title but rather, were written by loyal
followers or disciples of these people, often many years after their
death. In the case of St. Paul, however, we find that just over half of
the letters attributed to his name are believed to actually have been
authored by him since he was a learned man who could read and write. Of
the 13 Letters attributed to Paul’s authorship, seven are widely held to
have been written by Paul himself:  Romans, 1 & 2 Corinthians,
Galatians, Philippians, 1Thessalonians, and Philemon. The authorship of
six letters attributed to Paul is disputed:  2Thessalonians, Colossians,
Ephesians, 1&2 Timothy, and Titus (the last three widely held as being
written by someone other than Paul). It is important to know that this
“discovery” has not led the Church to question the divine inspiration of
these texts. Rather, it has only deepened our understanding of the
process by which Biblical texts were inspired by God.