Using Outlook to Send Texts

According to Constant Contact, only one in about five email recipients actually open their email.
Contrast this with the statistic that 98% of text recipients open their texts.
This should give you a feel for these 2 communication channels and how you should adjust your outreach to your target audience.
This link has more interesting statistics on email versus text outreach including how long readers interact with the message and the average response time of a text vs. email.  Text vs. Email
You can send texts via email if you know the cell service provider for the telephone.
I would not suggest overloading your clients with texts in this way or they may block your communications.
It is, however, a great way to make sure your message gets through when it is very important – or requiring a quick response.
The following article explains how to text using email.  Outlook to Text Article