What is the phone with 4g written icon in the notification bar? I have a Moto G6 with Vodafone Gujarat India.
That signifies the "VoLTE" calling. Because now your call is made over the LTE network, which is different than how they used to be placed earlier. Vodafone had launched VoLTE in many states but it's been a good time since they were launched in Gujarat. Surprising that you're noticing it only now.
VoLTE brings HD voice quality and faster call connect times. So, you get a lot of improvement in the experience.