You can make calls to your customers by using any of the click-to-call APIs that are available in this section, which you can utilise to reach out to your customers.
The need for customised click-to-call APIs has increased in parallel with the development of new technologies. Therefore, in order to better serve you, we have developed 4 different forms of click to call functionality, any of which can be used on an as-needed or case-by-case basis. As a reference for you, I'm also posting some screenshots here.
Click-to-call Use case Diagram: