VoIP, or Voice over Internet Protocol, allows users to make voice calls using a broadband Internet connection instead of a regular phone line. It has become popular due to lower costs compared to traditional phone service, especially for international calls which can be free with VoIP. Businesses use VoIP in various ways like making computer-to-computer or computer-to-phone calls to cut phone bills. VoIP services work by transmitting voice data in packets over the Internet or through a SIP trunk.