Open the Mail app
Go to Mailboxes
Open the Trash or Bin folder
Find the deleted email
Swipe left on the email
Tap More
Tap Move Message
Select your Inbox or another folder
If the email is not in Trash, check the Archive folder
Check the Junk folder
Check other mail accounts added to the iPhone
Open the Mail app
Tap Mailboxes
Tap Trash
Tap Edit
Select the deleted email
Tap Move
Choose the destination folder
If using iCloud Mail, log in to iCloud.com
Open Mail
Check the Trash folder
Restore the deleted message if available
If using Gmail, open Gmail in a browser
Check the Trash folder
Move the email back to Inbox
If using Outlook, open Outlook on the web
Check Deleted Items
Restore the email
Check whether the email was permanently deleted
Restore from a recent iPhone backup if needed
Open Settings
Tap your name
Tap iCloud
Tap iCloud Backup
Restore the iPhone from a backup that contains the email
Contact your email provider if the message is still missing