how do I convert a document to word .docx that someone not using an apple device can open

https://support.apple.com/en-us/HT202227#pagesformac

What document? An existing Pages document? If it is a Pages document, then open it in Pages, and from the File menu, choose Export To : Word and the default will be .docx. Save it to your Desktop. You can also choose the Share menu : Send a Copy : and choose Mail. It will open a new Mail compose window with the Word .docx attached, and you can finish and send the email.