1. To change the orientation of the whole document, select Layout > Orientation.

  2. Choose Portrait or Landscape.

Page orientation

Change part of a document to landscape

A landscape page in an otherwise portrait document lets you fit wide elements like tables and diagrams onto the page

  1. Select the content that you want on a landscape page.

  2. Go to Layout, and open the Page Setup dialog box.

    Page Setup

  3. Select Landscape, and in the Apply to box, choose Selected text.

    Apply to

Source: Microsoft