Here is the answer to this question: You need to send a 25 MB legal document to a client. However, their corporate email allows attachments of only 5 MB or fewer. You select File > Save As > Reduced Size PDF. This doesn’t reduce the file size enough, because the file has many photographs. Now you need to subdivide the document into smaller individual files. Where can you go to accomplish this?
Tools > Organize Pages > Split Document
Tools > Index
Tools > Edit PDF > Crop Pages
Tools > Optimize PDF