Registering an application will add the application to your Team Site in SharePoint Online. It also confirms to SharePoint that the application is trusted for:
You must have:
https://<companyname>.sharepoint.com/_layouts/15/appregnew.aspx
Note: If you are not logged on to Office365, log on when requested to do so.
For On Premise deployments, this should include your server name and the port number of the website. By default, the port number is 10444.
For example, <Your Sage200 server machine name>:10444
For Sage 200 Onlineonline, this should include your site name and sage200online.com.
For example, <Your site name>.sage200online.com
For on premise, this would be:
https://<Your Sage200 server machine name>:10444/Sage200SelfService/Office365/
For online, this would be:
https://<Your site name>.sage200online.com/Sage200SelfService/Office365/
The Redirect URL takes the details and writes them to the config database and completes the operation.
Note: Keep a note of your Client ID, Client Secret, Title, App domain and Redirect URL so that you can enter this information into Sage 200 System Administration.
What do you want to do?
Enter or amend application details in System Administration
Complete integration in System Administration
Add permissions in SharePoint Online
Reference
Tip: For the most recent version of this topic, please see our help website here.