Using pdftk to merge multiple pdf\'s is working well. However, any easy way to make a bookmark for each pdf merged?
I don\'t see anything on the pdftk docs regardin
Sejda PDF (which was suggested in one of the answers) is also available as an online service: https://www.sejda.com/merge-pdf.
This might come in handy if you don't want to install any additional software and prefer working online from a browser.
Steps to merge:
By default all existing bookmarks are preserved and will work in the merged document as well.
Optionally, the merge tool can build a table of contents based on the PDF documents being combined
The online service to merge PDF files is free to use for up to 30 files per hour and files up to 50Mb/200 pages.
Disclaimer: I'm an open source dev working on Sejda.