Skype

cant say anything about this app every one knows about it million of users world wide clear voice and video call, free of cost Download

Line

another app works like imo, whatsapp, viber is line i use this app far before when i use Symbian or java Nokia phones after that this is going more & more updated now.
LINE reshapes communication around the globe, bringing you closer to your family, friends, and loved ones for free. With voice and video calls, messages, and a limitless variety of exciting stickers, you’ll be able to express yourself in ways that you’ve never thought possible. With over 600 million users worldwide, LINE’s constantly expanding platform will continue to provide exciting new experiences and convenience.

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