How to stay calm during an interview?

Being nervous during an interview is natural but the best way  to help you calm down during an interview is to thoroughly explore the business or  research about the company. This involves looking  at social media, potentially speaking to current or past employees, and figuring out why they personally want to work for the company, you can see this in their "about us" page.
Next, keep in mind that you are there to present yourself and the reasons you want to work for the company. The keys are your résumé, awards, accomplishments, and the abilities you will provide. You are prepared if you are sure of the knowledge and abilities you will bring to the table. Being true to yourself throughout the interview will also ease anxiety. It's challenging to hide who you really are, and doing so will only result in unneeded tension. The business ought to desire the genuine you.

Finally, almost every interview begins with a sort of "Tell me about yourself." It will help you start the interview with a strong first impression if you've chosen in advance how to introduce yourself. Practice a 60-second intro several times in your head, while driving to the interview, and in the shower before interviews. Since you've had practice, you'll get off to a good start and maintain your composure throughout the rest of the interview.