To enable text notification you must sign-in on the web application and go in "My notifications".
Activate Text Notifications
Check the box "SMS"
Add your phone number
A code will be sent by text to your phone
Confirm
Your text notifications will now be activated.
IMPORTANT
It could take up to 5 minutes until you receive the text. If you don't receive it after such length, you may want to redo the above steps.
Stop Text Notifications
Go back in "My notifications"
Click on Disable text notifications