Creates a sms: link
Add block - Utilities - Social - Contact
This uses the sms: url scheme
Numbers should be in international format if you want to be able to receive texts from other countries
<xt:click2sms tel="0123 456 789" text="sms me" />
sms me
The above example creates this link
<a href="sms:0123 456 789" class="xt_button">sms me</a>