Hi,
There are a number of subjects you can study abroad. But first you will have to decide which stream you want to pursue.
Humanities,
Social sciences
Technical  (apart from CS)
MBA

Also you need to decide the country you would like to study.
For most masters degrees around the world, you need to appear for GRE.
MBA degree requirements include GMAT.

Additionally, you would be required to score well in English proficiency tests.

Please do revert if you need more information.