Where is the search box in emails?
how to get back search box in emails?
iPhone 8, iOS 11
Question marked as
If using Apple's default mail App, there is a search box at the very top of every MailBox / Inbox.
Open a mailbox / inbox, and then swipe down to reveal the search box.
Search for email in Mail on iPhone - Apple Support
If using a 3rd party mail app, it depends on the app.