Do one of the following:
Add line numbers to an entire document
Add line numbers to a selection of text
Microsoft Word will add page breaks (page break: The point at which one page ends and another begins. Microsoft Word inserts an "automatic" (or soft) page break for you, or you can force a page break at a specific location by inserting a "manual" (or hard) page break.) before and after the numbered lines.
Add line numbers to a section
Note To see the line numbers, switch to print layout view (Print Layout view: A view of a document or other object as it will appear when you print it. For example, items such as headers, footnotes, columns, and text boxes appear in their actual positions.).