How to delete all emails on iPhone

This is ridiculous. The trick worked once for me but today all the emails disappeared from the selected account and yet it says I have over 4,000 unread emails in that account. They are not visible so I can't do anything with them. Is there a way to truly clean out that mailbox?

Good thing you're not holding your breath. You'd likely pass out from lack of oxygen.

If this feature is important to you, telling us users on this forum won't get Apple's attention in the least. Let them know via this feedback link: Feedback - iPhone - Apple

In iOS 11.2.5 on an iPad I select inbox then ;

Tap edit

select the first three emails

hold down move ( don’t release )

unselect those three emails ( tap on each one )

release move

your then at your folders area - now approximately 7 rows down tap TRASH

Wow! I shudder to think about how long it took you, or someone else, to find that! Maybe an insider leaked it out! Anyway, c'mon, Apple. Fix this! Oh, unless you trying to "help" us purchase iPhones with greater storage capacities.

Again, snark. There are legitimate reasons that I accumulated over 1000 on my phone, but to you, it's black or white - either my emails are up-to-date, or I am not "taking responsibility". I don't owe you an explanation as to why, but my request was legitimate, and I solved it here, with a couple of snarky detours along the way.

I have always found this forum to be helpful, so if you can't be helpful, why not go post somewhere else?

I'm just saying ....

The Trash is grey and can't be selected iOS 11.0.3.

Yes, I was snarky and shouldn't have been. But then you were too when you accused Apple of trying to force people to buy a phone with more storage. Still, two snarks don't make a right.

How can I delete my one thousand + email all at the same time rather than one at a time

OMG you’re a genius!!! Thank you so much...you just saved me hours. I had over 4,000 emai, and they were gone in less than 10 seconds.