Answer

When you type in a document, Word automatically counts the number of pages and words in your document and displays them on the status bar at the bottom left of the workspace.

Word 2016 display of page and word count in a document

If you don't see the word count in the status bar, right-click the status bar and click Word Count.

Or, you can select Review from the menu bar and then select Word Count.

Screenshot of Word count option in the Review tab