Yes, native video call can be done without any reliance on internet and application. But for that, you will need 3G SIM and handset. Also, I am not sure if this is possible on every brand’s handset. As far as I know, the facility is available on Samsung, Micromax, Jio and Xioami.
Video calling without internet connection is fairly easy. You just punch the number and you will find a video calling tab right in the default dialer. Press it and instead of voice call that you regularly do, it’s going to be a cam call. Of course, for the call to happen successfully, the other party too must have a compatible device.
But remember, video calling without internet would cost you very high. The charges depend on your carrier. I would always advise to recharge your number with an internet pack and do unlimited video call without worrying about the charges.