If you added section breaks to your document, the easiest way to see where they begin and end is to show formatting marks.
Click the Home tab, and then click Show all nonprinting characters.
Click the section break to select it and then press DELETE. Section breaks look like this:
Note: When you delete a section break, Word combines the text before and after the break into one section. The new combined section will use the formatting from the second section (the one that followed the section break).