how to transfer email on ipad to ipad desktop folder

You might create PDF copy of the email - and store this in a folder along with other files. This takes a few easy steps; the description is far more complex than than the action itself…

To create a PDF copy of an email, tap the reply “arrow” at bottom-right of the mail window to open an action menu. From here select Print. This will open the print dialogue - to the left of which you will see thumbnail images of each page of your email.

Using the two-finger zoom gesture (i.e., the opposite of the two-finger pinch), open any one of the thumbnails to open the print preview page. Tap the Share button at top-right (a square with an upward pointing arrow) to open the Share Sheet. Finally select Save to Files, navigating to a location and folder of your choice, then tap Save.

You can now close-out/cancel any windows through which you have navigated that remain open, including the Print dialogue.

Your saved PDF file (your email message) can now be accessed using the Files App.

The native iOS/iPadOS Mail App does not have native capability to bulk-export email, from mailbox folders, to other storage locations.