Each Word document begins with one section, but a document can have multiple sections. Many of the formats you might think of as "document" formats are actually section formats, applying to a specific section:
- Paper size & page orientation (landscape vs. portrait)
- Page number style (i, ii, iii, iv or 1, 2, 3)
- Header and footer content
- Page margins (left, right, top, and bottom)
- Number of columns
Whenever you wish to modify these settings "mid-document," you must insert a section break, which effectively breaks the document into smaller "pieces." Each new section inherits the formatting from the previous section by default. After creating a section, you can apply different section formats to the new section.
Page orientation is one example of a section format. Each new blank document begins with portrait orientation, as defined in the section formatting of the Normal template. If a certain part of a document requires a landscape orientation, perhaps to display a wide table, you would need to break the document into sections so that each section could have an appropriate page orientation.
You might have a four-page document that should lay out like this:
The document needs to be broken into three sections, because the page orientation changes twice. There would need to be a section break at the end of page two, which would cause pages 1-2 to become Section 1, with a portrait page orientation. There would be a second section break at the end of page three, causing it to become Section 2. You could change the page orientation for Section 2 without affecting other sections. Page 4 would be Section 3.
Page margins (left, right, top, and bottom)
To change page margins, you must insert a section break as well. However, remember you can achieve similar effects, often more efficiently and more accurately, by changing the paragraph margins, or indents, as covered earlier. Paragraph indents are offsets from the section's page margin.