SharePoint Online: How to Create Alerts in Office 365 Security & Compliance Center?

Office 365 Compliance & Security center lets you to create alerts for specific events that occurs in SharePoint Online sites, such as permission changes, file-folder manipulation, etc. Let's see how to create an alert when someone shares a file of folder with external users in SharePoint Online:

Create Alert Policy for SharePoint Online in Security & Compliance Center
Here are the steps to create alerts in Office 365 security & compliance site:

• Login to Office 365 Security & Compliance Center at https://protection.office.com
• Expand "Alerts" in left navigation >> Click on "Alert Policies" >> Click on "New Alert Policy" button.
  
• Provide a name your alert, add description, severity and select category and click on "Next"
  
• Select the Activity from the drop-down. In my case, I've selected "Shared file externally". Choose when to trigger an alert. You can also add a condition for this alert. E.g. events on specific site collection.
  
• Configure recipients (User to whom the alerts will be sent) and daily notification limits.
  
•  Review the alert settings and click on "Finish" button to complete creating alert.
  

You should see "Alert Policy has been created" popup message and here is the alert in action when someone shares a file or folder with external users: