Altinn Notification SMS mobile number specification

content/notifications/send-notifications/get-started/user-guide/_index.en.md

@@ -13,8 +13,18 @@ In the meantime existing guidelines for sending notifications through Altinn 2 a
 [Please familiarize yourself with existing documentation and guidelines](https://altinn.github.io/docs/utviklingsguider/varsling/)
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+## Notification
+### SMS
+- Mobile number must conain country code, perferrably with "+", while "00" would also work. i.e. +47900XXXXX, 0047900XXXXX
+- Notificaiton to 5 digits number aren't supported. Therefore the mobile number must need to be more than 5 digits.
+- Norwegian mobile number must need to start with "4" or "9" after the country code "+47".
+  - Valid Mobile Number Example: +47400XXXXX, +47900XXXXX, 0047400XXXXX, 0047900XXXXX
+  - Invalid Mobile Number Example: +47500XXXXX, +47600XXXXX, 0047500XXXXX, 0047600XXXXX
+
+# International Mobile Number
+- We aslo support international mobile numbers(outside of Norway) to send SMS as long as they are valid and provided with country code.
+- Notificaiton to 5 digits number aren't supported. Therefore the mobile number must need to be more than 5 digits.
+- Mobile numbers are validated against a list of country codes. You can see [the country codes here](https://github.com/google/libphonenumber/tree/master/resources/metadata).
 
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