• The term describes a user interface that allows the user to view something very similar to the end result while the document or image is being created. For example, a user can view on screen how a document will look when it is printed to paper or displayed in a Web browser.
• It implies the ability to modify the layout of a document without having to type or remember names of layout commands.

Modern software does a fairly good job of optimizing the screen display for a particular type of output. For example, a word processor is optimized for output to a typical printer. The software often emulates the resolution of the printer in order to get as close as possible to WYSIWYG. However, that is not the main attraction of WYSIWYG, which is the ability of the user to be able to visualize what he or she is producing.

In many situations, the subtle differences between what you see and what you get are unimportant. In fact, applications may offer multiple WYSIWYG modes with different levels of "realism," including:

• A composition mode, in which the user sees something somewhat similar to the end result, but with additional information useful while composing, such as section breaks and non-printing characters, and uses a layout that is more conducive to composing than to layout.
• A layout mode, in which the user sees something very similar to the end result, but with some additional information useful in ensuring that elements are properly aligned and spaced, such as margin lines.
• A preview mode, in which the application attempts to present a representation that is as close to the final result as possible.

Applications may deliberately deviate or offer alternative composing layouts from a WYSIWYG because of overhead or the user's preference to enter commands or code directly.

A common understanding is that this does not mean "Similar", as stated above, but as close as possible, is an "exact representation" of what the appearance will be.