Some of the interviews will be through a meeting app similar to Microsoft Lync. You will have to call in or sign in the meeting.
They have recruiters that have very strong and fast Indian accents, so some may be unprepared for this. I work with a lot of Indians and adapted pretty well to their accents, but even I had a hard time understanding.
The phone screen by recruiters will be tougher than most recruiter calls. It's tougher than 90-99%. So basically, it's a full blown interview. Prepare for it as you would prepare for any interview.