Classification can be defined as the process of assigning headings to documents in order to group or classify them according to certain common characteristics prior to filing.We are all aware that the primary goal of file classification is to ensure the rapid availability of information whenever it is required. Classification enables the filing functions to accomplish these primary goals.

A filing system’s efficiency, and particularly its accessibility, is highly dependent on the care with which documents are classified. By classifying similar paper or papers belonging to a specific head or subject, office staff can quickly and easily locate the paper or documents required at any time.Methods of Classification of files are:-

• Alphabetical classification:The most frequently used method is alphabetical filing. The papers or records are classified alphabetically according to the first letter of their names in this system of classification. The Telephone Directory is an excellent illustration of this type of classification.For instance, correspondence with individuals whose given names or surnames begin with the letter ‘A’ will be classified and arranged alphabetically. If several names begin with the same letter, the arrangement takes subsequent letters into account as well.The alphabet’s main divisions can be further subdivided, and color coding can be used to facilitate file selection and replacement. Alphabetical classification can be done by name, subject, or geographical location.
• Numerical classification: Each folder or record is assigned a number, and the files are organized numerically, i.e., each customer or subject is assigned a number. All papers pertaining to a specific customer, supplier, or subject are grouped together in a single folder with a unique number.

  Folders are organized numerically in the cabinet, and guide cards are used to divide them into groups of 10 or 20. As a result, if a customer is assigned the number 14, all of his papers and documents will be found in folder number 14.To make it easier to find and refer to a specific file, an index will be required.Types of Numerical Classification include:-

1. Consecutive Classification System: Folders or files are arranged in strict numerical order from one onwards in this classification. Each folder is numbered and labeled with a subject or name before being placed at the back (rear) of the existing folders.
2. The Dewey Decimal System: This system is very popular in libraries because it is easy to use. Each digit represents a different sub-classification in this system of classification.
3. Terminal Digit System: File numbers are read in groups of two or three from right to left, with each group representing a specific location or other coding.

• Geographical classification: Files are organized in this system according to the location or addresses of the people or parties to whom they pertain.Street-by-street, town-by-town, district-by-district, state-by-state, or country-by-country classification is possible. Only when combined with either a numerical or alphabetical system will this system work effectively.This classification system is commonly used by companies that engage in export trade or do business across a large geographic area. This classification system is used by mail order houses, banks, and insurance companies, among others. This system is also appropriate for businesses that require records based on sales territory.
• Subject-wise classification: This system consolidates all documents pertaining to a particular subject into a single file. This document could have originated from a variety of different sources and individuals.This system is used only when the subject or content of a letter takes precedence over the correspondent’s name. Each subject is kept in its own file. These files can then be organized alphabetically, numerically, or in any other way that makes sense.For instance, separate files may be kept for purchase quotations, purchase orders, income tax returns, and travel expense bills, among other things.
• Chronological classification: Records are filed in strict date order under this arrangement. This is how records such as vouchers, invoices, bills, and other bills related to accounts are organized. This system, on the other hand, cannot be adopted on its own.Documents should be categorized by subject and then placed in chronological order within the file corresponding to that subject.