This is an app that duplicates pages in a PDF-file in a few different ways. It can do a lot more page copying and arranging than the free app Duplicate pages.
It can still do what the free app does but also duplicate pages in multipage PDF’s, one options is to duplicate the file as it is. This means that that page range is intact but repeated as many times as you want the copies to be. For example an 8 page file with the setting to make 4 copies will result in a file in the order 1-8, 1-8, 1-8, 1-8 in all 32 pages. The other option is to take all pages and copy the sequentially i.e. 1111, 2222, 3333, and so on until the last page 8,8,8,8.