EQ Flex can send SMS text messages, once you have purchased credits. See Postcodes & Text Credits for how to setup sending and buy credits.
This article covers how to use EQ to send text messages to many recipients. Example use cases could be to remind customers of upcoming showroom appointments, fitting dates, send your contractors/sales people reminders of bookings.
Here is a video showing filtering of Projects > Communication, applying and saving a filter and using a text message template to send to all upcoming appointments.
The same steps can be used to send an email in bulk, too. Just select Email from the top menubar.
Further reading