VoIP software has many different purposes and functions. Overall, the VoIP software you will most likely run into (and run) is called a softphone.
Software for VoIP is not only necessary to make VoIP calls and manage digital communications but, in general, VoIP software can make certain tasks easier, cheaper, and more organized.
Businesses also need software for VoIP PBX servers, especially if a business wants to cut down on PBX hardware. Any business that needs to manage customer relations can also use VoIP-integrated CRM (customer relationship management) software.