The Google Drive app which comes pre-installed on almost all Android devices has an in-built PDF reader, however, for Android for work environments where the Google Drive app isn’t deployable, Google has released a standalone PDF Viewer app to Play Store which serves the simple purpose of viewing PDF files.
Google mentions this explicitly in the app’s description over at Play Store that the Google PDF Viewer is primarily meant for Android for Work program, but of course it’s available for anyone to download.
PDF Viewing is now available directly in Google Drive. For environments where this cannot be deployed, Google PDF Viewer offers the same capabilities in a standalone app. View, print, search and copy text from pdf documents while you’re on the go.
Note: PDF Viewer is primarily meant for use in the context of the Android for Work Program (http://android.com/work).