Final answer:
To insert an accent bar over a number, place the cursor where needed, use 'Insert Symbol' or a keyboard shortcut, and add the macron, adjusting your header or footer if necessary.
Step-by-step explanation:
To insert an accent bar, also known as a macron, over a number in a word processing document like Microsoft Word, you should first ensure your cursor is placed where you want the number with the macron to appear. Then, you can use the 'Insert Symbol' feature or a specific keyboard shortcut, if available for your operating system, to add the macron. If you wish to display the page number with an accent in the header or footer of your document, you can access the 'Header & Footer' tools, and once there, insert the special character as needed. Keep in mind that the exact methods may vary slightly depending on the software and version you are using.