The original formatting and data of each PDF files won't get lost or changed in output PDF file.
Online On Windows On Mac Community Q&A This wiki How teaches you how to combine two or more PDF files into one file.
Preview can edit and merge pdf files but the official Apple instructions are not quite right.
Here’s how to do it depending on which version of OS X that you have.
When you drag in step 3 it must drag to on top of the thumbnail, as in it.
This is a bit hard to explain, the best way to grasp the concept is to look at the pictures below.
Just drag all of the PDF and image files that you want to consolidate into the main window.