Google Duo is a video chat app for adnroid and iOS devices. Some Android devices come with Duo already installed, but if you don't find it in yours you can download it for free.
You can use Google Duo to video chat with up to 12 people at once. If you are looking for a video chat app to keep in touch with friends and family, Duo will suffice. It has a unique feature called Knock Knock which allows you to see a preview of the person you are calling. If you don't like Knock Knock you can disable it.
Many people have turned to Google Duo because it's very easy to use. The icon appears on every contact on your list who has it, and to initiate a video call you only need to hit the green button. You can activate your camera to show someone your surroundings, and you can also mute audio.
You don't need to have a very fast internet connection for Duo to work; most people are able to use it without interruptions.