How do I merge multiple pdf/a files into one pdf/a file and then index and insert page numbers?

[marshah92177271]

I have Adobe Acrobat DC.  I have converted a number of documents to pdf/a files.  I want to put these into one pdf/a file.  I also need to make and index and number the pages.  I am at a loss.

[Test Screen Name · Accepted solution]

PDF/A files are FINAL files, not meant for editing. So if you want to do further editing you need to turn them into ordinary PDF files, combine them, number them, then make them PDF/A files. If they are tagged, this may be a nightmare with weeks of work to resolve.

Indexes are added in the original application, not once you have a PDF.