The following link an excellent resource for information about the books of the New Testament.
https://bible.org/series/new-testament-introductions-and-outlines
For example, let’s say that you are interested in learning about the evidence for the authorship of John. The link on the book of John covers external evidence that starts with mentioning Irenaeus and other church fathers that affirm its authorship to John the apostle. It also lists internal evidence of two types: concentric proofs and incidental evidence. There is even a section responding to arguments against Johannine authorship.
The information on the books of the New Testament is compiled by the very prominent New Testament scholar Dan Wallace at Dallas Theological Seminary.