public class triggerHelperClass {
public static void updatePostal(List<account> triggerNewList){
   for (Account a: triggerNewList)
   {
   if(a.Match_Billing_Address__c==True)
   {
   a.ShippingPostalCode=a.BillingPostalCode;
   }
   }
}
}

hai
here i created to different recod types for opportunity object.so when i want to create new opportunity record it first asks me record type selection .so how can i skip this page when creating new record?