By default, a document is in Landscape, so the long edge is at the side. If you are producing for example a document with a lot of data going left to right you may need to switch orientation.
You can do this from the Format —> Page Styles option.
This allows you to switch your DOCUMENT to Landscape, so the long edge is at the top, or back to portrait.
You can also use the Insert menu to add a new page which is a different orientation, this uses page breaks.
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