Your company will need to have SMS Notifications enabled in their account in order to enable this functionality.
To receive SMS notifications, you must have accepted your manager/employer's RotaCloud invitation and created a login.
First, go to Settings > Your Details, add your mobile number into your profile (it may have already been added by your manager/employer) and Save at the bottom of the page.
Once you've entered your mobile number, you'll receive a text message asking you to verify your phone number.
Just reply with the word 'Yes' (without quotes) to verify the mobile number and complete the SMS setup process.
If you don't receive the SMS, you can go to Settings > Notifications and resend it via the blue bar near the top of the screen.