Use Of addFields in ApexPages.StandardController
The add fields method helps developers specify fields for the standard controller to query in Visualforce pages. public AccountController(ApexPages.StandardController stdController){ this.controller = stdController; List<String> fieldNamesList = new List<String>{Type,Industry}; stdController.addFields( fieldNamesList ); // stdController.addFields(new List<String>{'Name', 'TaxExemption__c', ' Industry '}); } Reference: https://developer.salesforce.com/docs/atlas.en-us.pages.meta/pages/apex_ApexPages_StandardController_addFields.htm