The default paper size in Microsoft Word is 8.5 x 11 inches –the standard size (called Letter), which conveniently fits in most printers and copy machines in the United States. You can choose a different paper size and orientation, though.
Whenever Word starts a new document, it does so based on a group of settings stored in a template called Normal. A template is a configuration file that governs the default settings for the documents that are based on it. These settings include specifications for a paper size of 8.5 x 11 inches. If you want the document to have a different paper size — say, for a brochure — choose Page Layout→Size and then choose a different paper size from the drop-down list.
In addition to Letter size, Legal size is the other major size used in the United States: 8.5 x 14 inches. In other countries, though, standard paper size is different. For example, in Europe, A4 paper is the standard size, at 8.27 x 11.69 inches.
Page orientation determines whether the height or the width of the page is greater. If the text is parallel to the narrow edge, that’s Portrait. If it’s parallel to the wide edge, that’s Landscape.
Portrait (taller than wide) is the more common orientation, used for most correspondence and reports. Landscape orientation (wider than tall) is used for brochures, certificates, and calendars, all of which fit naturally into the wider format.
To change the page orientation, choose Page Layout→Orientation and then click Portrait or Landscape.