HII All,
         Next visit should be greater than 30 days than Appointment Created Date:
       Next_visit__c<(Date value(Created Date )+30)
But its Showing An Error i.e, Error: Syntax error. Found 'Date'
 

HII All,
         Next visit should be greater than 30 days than Appointment Created Date:
       Next_visit__c<(Date value(Created Date )+30)
But its Showing An Error i.e, Error: Syntax error. Found 'Date'