So is WhatsApp however in this case I don’t know who did this project but will say it is not part of OpenEMR.
It was probably custom done by a vendor that used the OpenEMR brand for marketing purposes.
We have a SMS messaging module(Twilio) that is set up to support other messaging, email and fax vendors with a little effort. Hopefully if the vendor that did this decides to contribute it to the community there are modular resources in OpenEMR.