Unless your tablet can run windows (very unlikely), like the Microsoft Surface tablet and specifically the Microsoft Surface Pro running windows 8 pro (not windows 8 RT). Otherwise you can’t install the avast! antivirus program for windows systems.

If you have an Android tabled then avast! Premium (for windows) can’t be installed.

The avast! mobile security (AMS) should be OK depending on the tablet (?) and the android Operating System (?). If you have an android tabled with AMS installed then it is possible - as Filip mentions - to upgrade that the the Premium version.