Who decided the books in the Bible?

Believing that the Bible is 'God-inspired' is not enough.  Christians should ask who decided that the Bible books are 'God-inspired'.

How come some Bibles have more books than others?

Although I am not convinced that this article is entirely correct, it is a good reference.
https://st-takla.org/pub_Deuterocanon/Deuterocanon-Apocrypha_El-Asfar_El-Kanoneya_El-Tanya__0-index.html

To summarize:

1) Jesus, in His time, used the Septuagint Version (Greek) of the Old Testament Scripture.  The Septuagint includes the 7 additional Old Testament books now found in the Orthodox/Catholic Bible.
2) The Jews, during Jesus' time, did not accept Jesus' ministry.  Hence the Jews avoided the Septuagint, and hence the 7 additional books too.
3) After Jesus' death, the apostolic church continued to use the Septuagint Version of Old
Testament.
4) Even in the late 4th Century AD, in the Apostolic church, the Councils of Rome, Hippo, and Carthage, were using the 7 additional Old Testament books.
5) Right up to 1546, the church had been using these 7 additional books in the Old Testament.
6) Then came Martin Luther.  He rejected the 7 additional books, purportedly because these books contained scriptural proofs of the doctrines of the Orthodox/Catholic churches.
7) The New Testament books were agreed upon at the Council at Carthage in 395AD.

I often wonder whether or not it was a right thing for Martin Luther and the Protestant Movement to remove some books from the Orthodox/Catholic/Apostolic churches' Old Testament.  On balance, I think it was not a good thing.

By the way, the 7 additional books in the Old Testament are (total 46 books):
a) Tobit
b) Judith
c) 1 Maccabees

d) 2 Maccabees

e) Wisdom of Solomon
f) Sirach
g) Baruch
(reference: https://en.wikipedia.org/wiki/Old_Testament)