How to enable the audit log in SharePoint 2013

To enable the audit log by using Central Administration

·         On the Central Administration home page,

·         In the Application Management section,

·         Click Manage service applications.

·         Select the Secure Store service application.

·         On the ribbon, click Properties.

·         From the Enable Audit section,

·         Click to select the Audit log enabled box.

·         To change the number of days that entries will be purged from the audit log file, specify a number in days in the Days until Purge field.

·         The default value is 30 days.

·         Click OK.