=Invoices.= The method of filing invoices depends on whether or not a complete voucher system is used. When no voucher system is used, all invoices should be filed alphabetically in a vertical file. A folder should be used for each firm or person from whom goods are purchased, so that all of their invoices can be kept together. Invoices should be filed in the folder in the order of their dates, the last one in front. With the voucher system, invoices are sometimes attached to the voucher, in which case they are filed according to the voucher number and a separate card index is kept for alphabetical reference. The more modern plan, however, is to file the voucher numerically, retaining the alphabetical index for invoices. Invoices can be filed in the same file with the correspondence, or in a special file. When the former method is adopted a folder of a special color should be used. There would then be two folders for a firm, one for invoices and one for correspondence. Special folders with double folds are largely used for filing invoices, as shown in Fig. 23. [Illustration: Fig. 24. Document File. _Browne-Morse Co._] =Documents and Legal Papers.= For filing documents and legal papers, there are two standard methods. The older of the two is to fold the papers and file them on end in a document drawer, like the one shown in Fig. 24. The drawer is equipped with a compressor or following block for keeping the papers in an upright position, and either alphabetical or numerical indexes. These drawers can be obtained singly or in cabinets containing any number. The more modern method is to file documents and legal papers in a vertical file, using document envelopes, as shown in Fig. 25. These envelopes are of the right size to hold legal papers flat, insuring convenient reference, which is a decided improvement over the older method of folding the papers. Any of the several methods of indexing can be used, depending on the requirements of the business. [Illustration: Fig. 25. Document File Envelopes _Browne-Morse Co._] As a filing system for the lawyer's office, this method is unsurpassed. Every record of the office is kept in one complete filing system, yet each case is separate and distinct. Every paper and all correspondence relating to a given case is filed, unfolded, in one of the document envelopes--or a folder can be used--bringing all papers on the same subject together. If indexed alphabetically, the papers are filed according to the name of the client. When the numerical index is adopted, an alphabetical index card with cross-references, including the docket index, is used. The folders may be numbered by case or office numbers. Copies of opinions can be filed in the same manner, making every opinion available whether given yesterday or ten years ago. The usual confusion in the lawyer's office, incident to the search for papers scattered through several files, is entirely done away with.