My wife mainly uses the latest version of Exchange mail on her iPhone 13. She has many thousands of messages and many folders.

I often open her mailbox in Outlook 365 on my Windows 11 laptop to help with certain tasks.

Many of her folders are what I call sub-folders, below the Inbox. But the weird thing (to me) is that there are also many folders that are on the same level as the inbox.

Does this make sense? What is going on? Or should I even care?

Thanks in advance.