SLDSValidatordemocontroller.apex

public class SLDSValidatordemocontroller{

    public SLDSValidatordemocontroller(ApexPages.StandardController controller) {
    }
  @RemoteAction
    public static Id createAccount(String name,String fax){

        Account acc = new Account();
        acc.Name = name;
        acc.Fax = fax;
        
        insert acc;
        
        return acc.Id;
    }

}