Whether you tapped an email by mistake, iPhone Mail opened it automatically after you deleted another or you just want to keep a message highlighted: it's pretty easy to mark individual emails unread.
Mark Email Unread in iPhone Mail
To mark a message as unread in iPhone Mail:
- Tap the message to open it.
- Now tap Details if visible.
- Tap Mark as Unread.
- Make sure Mark as Unread is now gray (as opposed to web site link-blue).
