Create alerts on libraries or documents in SharePoint
Explains how to create an alert which will notify you of any changes in a document library, folder or to an individual document in SharePoint.
To set an alert on an entire list or library, click the Library tab at the top and click Alert Me > Set alert on this library.
Fill out the alert form as shown below and click OK:
To set an alert on a specific document, navigate to the specific document in the list or library. Select the document by putting a check mark next to the file and click the Files tab.
Next, click Alert Me > Set alert on this document and fill out the alert settings.