How can I remove a section break in Word?

If you added section breaks to your document, the easiest way to see where they begin and end is to show formatting marks. Go to Home, and select Show all nonprinting characters. Select the section break and then press Delete.

Can’t delete sections break?

If you have difficulty deleting a section break, click the View tab in the Ribbon and select Draft in the Views group.
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To delete a break:
  1. If necessary, click the Home tab and then click Show/Hide ¶ in the Paragraph group.
  2. Double-click the break to select it or drag over it.
  3. Press Backspace or Delete to delete the break.