A non-interactive user is a user account in Microsoft Dynamics CRM Online that can access the system but only via the web service layer.
This is ideal for Service Accounts such as Integration and Portal accounts as those accounts do not require a Dynamics CRM Licence.
For Dynamics CRM Online with Office 365, doing this can be abit tricky:
1. Add account to O365 and assign it a CRM Online Professional Licence
2. Assign appropriate security role(s) to the account in CRM
3. Change account Access Mode to Non-Interactive in CRM
4. Remove licence from the account in O365