Combine pdf documents, pageinate, add margin on top for adding heading, bookmark

I am looking for someone to help me combine a large number of PDF documents into one cohesive package. I need pagination in numerical order, as well as bookmarked titles for each segment. I have over seven documents that need to be combined, and all of the titles for the bookmarks are ready for use. The margin at the top of each page needs to be set up for adding headings. Can you help me with this project?