VF page Pdf Download with dynamic Name by Automation or Manually

 You can write below Syntax in your vf page Constructor

Auto- Download

            Apexpages.currentPage().getHeaders().put('content-disposition', 'attachment; filename='+ord.Order_Confirmation_Date__c+'.pdf');

Manually Download:

            Apexpages.currentPage().getHeaders().put('content-disposition', 'inline; filename='+ord.Order_Confirmation_Date__c+'.pdf');