Video calls are an excellent option for connecting in a more deeper way with your fans.
You can enable or disable them and configure them from your account, in the section: Settings > Privacy > Video Calls.
In that same location, you can set the price per minute and the duration for these interactions.
Important: For users to be able to call you, your visibility status must be set to "Visible". If you are set to "Invisible", they will not be able to initiate the video call.