It’s easy to add bates-numbers to PDFs using Acrobat. If the documents you want to bates-stamp are not yet in PDF format, then you need to scan them or convert them to PDF. If you have Acrobat 8 or 9 simply follow these instructions, which begin by having you do this: choose Advanced > Document Processing > Bates Numbering > Add.
The instructions are the same in Acrobat X, except that you’ll have to click on on the Tools menu over on the right, then >Pages > Bates Numbering > Add.
Once you’ve bates-numbered the documents you can search for documents based on the bates-number. Choose Edit > Search, and then as the search word or phrase, type in all or part of the Bates numbering that you want to find.
Pretty easy, isn’t it? Makes you wonder why anyone would do it the old-fashioned way.
Source: PDF for Lawyers