Skype is free for calls to other Skype users over the internet, making it very popular for staying in touch with friends, family, and business contacts all over the world. In order to do this, the Skype software relies on your device's camera and microphone to capture and transmit your live image and voice, as well as your monitor and speakers to deliver the other person's image and voice to you. You can make "calls" and talk to just one person, or add people to a call and have a group conversation or meeting.
It supports a variety of devices, including computers (Windows, Macintosh, Linux) and portable devices running iOS (iPhones and iPads), Android, etc. Skype is an extremely popular online service that lets you talk to other Skype users over the internet in three ways: Using both voice and video, voice only, and instant messaging (i.e., typing back and forth). Skype: The Top Good (and Bad) Things You Should Know