Page numbers are the most common type of header or footer. They're such a necessary element in documents that they get their own button and gallery of choices.
To add page numbers:
On the Insert
tab, in the Header & Footer
group, click Page Number.
Choose where you want the numbers on the page, at the top or on the bottom, for example.
Then choose a page number style from a gallery of possibilities.
The page numbers are applied throughout your document. Also, they're set up to automatically renumber if you add or delete content in the document.