There are many ways/methods one can use to communicate in some way with another person. There are also many applications that make it easier to start this communication. Some you will know and other are less common. All the applications below will help one person communicate with another entity in some way (sometimes it is just a diiferent way to communicate with your device).
Skype
Signal / secure messaging
Twitter
Facebook
LinkedIn
Pinterest
Other Social Media apps
Hootsuite
Other multi-Social Media platforms
Zoom