Please, read my comments first.
There aren't 2 tables! There are 2 source tables and one destination table only, because you joined them with
INNER JOIN
statement.
SELECT it.id, it.Code, it.Description, it.Rate, it.Bottles, it.Supply,
it.Empty, it.Amount, it.Received, cn.Opening_Date, cn.Clients_Title, cn.Cust_Id
FROM Items AS it INNER JOIN Customer_New AS cn on it.Cust_Id=cn.Cust_Id