As of Plus 7.0, video calls have been added to the app.

To use video calls, navigate to the other person’s profile. Then click the video call icon, to the left of the call icon.

Notes:
• Both you and the person you’re trying to video call need to be on 7.0 or above.
• If you do not see the video call icon, make sure the other person accepts calls from you and has updated their app.
• Any issues with video quality, lag, etc. will have nothing to do with Plus. You will need to contact Telegram Support if you want to report any problems with video calls.

Update the app:
click here