Yes. It is necessary as there may be many appendices such as Appendix A, Appendix B, Appendix C and so on. They need to be enunciated after a ':' mark.
A table of contents is a page or pages that include information on each subject in that paticular book..
It's actually the same thing.
It's just a list of divisions/chapters/articles of a book, and it lists the corresponding page numbers.