Users can configure individual alerts on document or list-related activities to be notified on certain events such as modifications or deletions. Site Administrators can also create alerts on behalf of other users. Alerts are configured on specific lists or libraries.
Site Administrators should configure alerts for themselves on libraries containing critical documents, especially for deletions. Site administrators have up to 90 days to recover deleted documents from the recycle bin, so an alert will proactively notify you that documents have been deleted and give you enough time to restore them if necessary.
From the applicable list or library, expand the ellipsis (...) on the menu and select 'Alert me'
Give the alert a title (useful if you have multiple alerts configured) and then choose the appropriate activities you want to be alerted to. If you expect many conditions to be triggered, then consider using the summary options so that you are not bombarded with emails.
Create an alert as instructed above. In the Users field, simply add multiple users.
Individual users can manage their alerts, by selecting 'Manage my alerts'
From here you can delete alerts and add new ones. Note that you cannot modify an existing alert--you have to delete and recreate it.
Site Administrators can see all the alerts created on a site and delete them. Go to Site Settings--Site Administrator--User alerts.
From here, select a user from the drop down to see their alerts.