For example, if clerks in looking for a certain order could always give the order number, but not the name of the customer, it would be wrong to file the orders alphabetically; in such cases, file the orders numerically. Always file papers according to the information which the clerk or executive will have at hand when looking up the same. Sometimes, papers will be just as easily found when filed numerically as alphabetically. =Reference Information.= One very important feature to remember in designing forms is to place all reference information on the right-hand side of the sheet. In leafing loose sheets held in binders, it will be easy to find the desired sheet if this plan is followed; but, if the reference numbers are placed on the left side of the sheet, it will be necessary to open the binder relatively wide to see each number. In the illustration, Fig. 23, it will be noted that the order number is properly placed, and that the printed headings are aligned horizontally at the back, which permits all typewritten matter to be started evenly. The value of this point was touched upon in a previous chapter, as to saving of time in the execution of the work. In this particular form, however, there is typewritten matter to the left of the headings, such as _account of_, _ship to_, etc. The marginal stop on the billing machine should be set for the first typewritten matter, and tabulator stops used for all matter to the right on each line. COMPOUND FORMS One of the most effective means of short-cutting work, where the nature of the business will permit, is through the use of compound forms. These forms derived their name from the combination of order and billing work on one set of sheets and accomplish in one operation, sometimes in two, all the clerical work incident to the receipt, registering, acknowledgment, billing, charging, and shipping of an order. It can be readily seen that if a firm can fill its orders completely, or almost so, that there is no use to wait until the order is filled before billing it. It is a great deal easier to place another sheet along with the order forms and use it for an invoice. It is generally placed as the top sheet of the set, and therefore it is the original. =Goods Shipped for Entire Order.= If the nature of the business is such that the firm can always fill its orders completely, it is perfectly safe to enter prices, make the extensions, and complete the invoice, with the possible exception of the date when the goods are finally shipped, if they cannot be sent out the same day. In such cases, a printed heading is provided on the invoice, opposite which the shipping date is typewritten. This then becomes the date of invoice. [Illustration: Fig. 23. The Colored-Sheet System. A Different-colored Sheet is Used for Each Department _Underwood Typewriter Co._ ]