Use the following code and execute in Anonymous Apex window to check the Daily Workflow Emails Limit usage

Sample Code:

Map < String,System.OrgLimit > limitsMap = OrgLimits.getMap();  
System.OrgLimit apiRequestsLimit = limitsMap.get( ‘DailyWorkflowEmails’ );  
System.debug( ‘Limit Name: ‘ + apiRequestsLimit.getName() );  
System.debug( ‘Usage Value: ‘ + apiRequestsLimit.getValue() );  
System.debug( ‘Maximum Limit: ‘ + apiRequestsLimit.getLimit() );