My emails disappeared from iCloud mail
My emails disappeared from iCloud mail on all my devices. How do I get them back?
iPad, iOS 9
The inbox mails are deleted and emptied immediately they are erased from iCloud server permanently Delete email in Mail on iCloud.com - Apple Support
Note : The mails you moved from trash to archive Archive email in Mail on iCloud.com - Apple Support will not be found , it depends you had iCloud archive feature always turned as on then old months back mails will be found in them .
Also if iPad and other devices like Mac / iPhone were synced ( signed in with same Apple ID say example1@icloud.com ) on the same network the mails deleted from iPad will also deleted from other devices .