Can I open certain files like pdf, epub in other applications?

Yes. EasiShare has an Open-In feature which allows you to do so.

1. Click on Open-In button in top right corner
2. Choose which application you like to use to open the document. 

Note: The Open-In feature may be disabled by your administrator if you noticed you do not have this function. See related article: Disable "Open In" on mobile devices