use of a computer program or a dedicated hardware and software package to write, edit, format, and print a document. Text is most commonly entered using a keyboard similar to a typewriter's, although handwritten input (see pen-based computer) and audio input (as for dictation) devices have been introduced.
Word processors have various functions that allow a person to revise text without retyping an entire document. As the text is entered or after it has been retrieved, sections ranging from words and sentences to paragraphs and pages can be moved, copied, deleted, altered, and added to while displayed. As word processors have become more sophisticated, such functions as word counting, spell checking, footnoting, and index generation have been added. In addition, a document's format—type size, line spacing, margins, page length, and the like—usually can be easily altered. To aid in these alterations, the text is displayed as it will appear when printed with indented paragraphs and lists, multiple columns, tables, etc; this is called a what-you-see-is-what-you-get (WYSIWYG) display.
Word processors are distinguished from text editors and desktop publishing systems. Text editors are designed for creating and editing computer programs. While they have features found in simple word processors, such as search and replace, that make the entry and editing of words and numbers easier, text editors provide only the most primitive facilities for text formatting and printing. Desktop publishers may include only simple word processing features but provide enhanced formatting functions, such as routines for merging text and graphics into complex page layouts.