Yes, you can watch World T20 on Hotstar. You will need to sign up for an account and then you can choose from a variety of subscription plans. The most basic plan is free but it only gives you access to certain content. If you want to watch World T20, you will need to sign up for the premium plan which costs $9.99/month. Once you have signed up, you can log in and start watching any of the matches that are being streamed live.