Hello,

The core part of your PhD interview will most definitely be related to your domain, that is your subject, and so be thorough with your graduation and post-graduation studies, and if you're planning to pursue PhD then most definitely you must have thought about research areas, so study well about that through books, online lectures, or any other available content, depending on the criteria of the institute you're applying you might have to submit research proposal, so check out if this applies to the university you're about to enroll for, the interview panel might want you to have a presentation in front of them when it comes to your topic, other than this be well acquainted with the university, just acquaint yourself with the department, the faculty which you can easily get the information by visiting the official website, just be your natural self, that's mandatory in any interview, and remind yourself that you have worked hard to complete your graduation and post-graduation and now about to enroll in PhD, and that itself should act as a confidence booster.