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Select My Apps in the top menu
Select Control Panel
Scroll down to Account section and select Preferences
Tick the Activate Messaging tick box
In the next box, select the Contact Form fields you would like to designate as being the ones that hold the mobile phone number of your contacts. You can select multiple fields
Press Save.
SMS Messaging is now enabled on your organisation.
Press the Messaging button in the top menu (it is shaped like an envelope)