Is it this sign you meant in your post? Then you should have chosen where to archive the email. In case you don't remember where you sent it:
In your Email app, tap the account (under Accounts) where you're searching for the missing email. This will show you the Mailboxes of this account (Inbox, Sent, ...). Most of the time, emails are sent to Archive:
Tap it and look for your email there. If it's not there, look into Trash.
There's also the possibility to search for it in your email app.