After your 12th studies you can get into various computer related courses namely,

Web designing/graphic designing
SEO/ SEM
Software testing
Programming and C++

You will learn basic skill over Computer, internet skills to surfing and Basic English understanding. Later as per your interest you can further do your graduation and then gain experience accordingly.

Whichever course you do, Diploma or certification course- whichever you choose, make sure that you do the course from a recognized and approved institute.

Good Luck.