Hi @Ed Railton ,
Welcome to our forum!
What's the version of your Outlook for Mac?(Outlook>About Outlook)
As i know, after you create a folder or subfolder in the navigation pane, you can change the folder's name or move it to a different location in the folder list. More information: Move or rename a folder in Outlook for Mac.
If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.