We all have some special people in our life. From whom we chat and call almost every day. So we put those favorite people in our favourite contacts.
Like all other apps Viber has this option of favorite chat and favourite contacts too. You can add your favourite people here and if you want to remove them you can remove them as well.
By tapping on the contact for some time the option will appear, add to favourites. From there you can add people to favourites.
How can you look at your favourite contacts? Go to settings search for your favourite contacts. There you will find your favourite contacts. It is easy to save people in favourites and there is no need to search them down in the chats.