How do I turn off page numbering in Word on my iMac?

Open the document that has page numbers. Double-click in the footer area where the page number appears. Then in the bar of icons at the top left of the Word window, click Page Number and then select Remove Page Numbers. Then double-click somewhere in the body of the document to get out of header & footer mode.

Have you clicked the Help menu in Word and then type "page number"??

Also, when posting you should post:

• Model Year of your iMac
• Version of Mac OS installed
• Version of MS Word you are using

Finally, as Word is a Microsoft product you should also look on the Office For Mac forums hosted by Microsoft. https://answers.microsoft.com/

Since Word is not an Apple product (Microsoft) if you can’t resolve your issue here then you should try Microsoft’s users support forums and ask there.