Set Up Alerts in SharePoint and Get Notified When an Item Changes

Stay informed about changes to files and folders in SharePoint by setting up alerts. SharePoint alerts are helpful for tracking projects and team collaborations, and for receiving prompt updates when documents or items change. Here’s how to set up alerts for a list, library, folder, file, or list item:

Get Alerts for Item Changes:

1. Navigate to the desired list or library.
2. Select the file, link, or folder for which you want to receive alerts.
3. Click on the ellipsis (…) from the list of options for the list or library, then select Alert Me.
4. Customize the settings in the Alert me when items change window with a title and description.
5. Choose the criteria for when an alert should be sent. Select relevant filters to avoid receiving too many notifications.
6. Click OK to save the alert.

Cancel Alerts:

1. To view your alerts from a page on the site, click on the ellipsis (…) from the list of options for the list or library, then select Manage My Alerts.
2. Select the alert that you want to delete, then click Delete Selected Alerts. 
3. Click OK to delete.

Source: Create an alert to get notified when a file or folder changes in SharePoint