You are downloading the PDF + AppX file v18.104.22.168 for Windows Phone. PDF + is a free and useful Productivity app: PDF + allows you to quickly view Adobe PDF documents. ... You can now download the offline AppX file to install & try it.
Download Locations for PDF + 22.214.171.124 AppX file
Note: To install it manually from an SD card, you should choose one of the server location above to get the offline PDF + AppX file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.