In iOS 9, you could organize emails in Apple's stock Mail application by thread but that was pretty much it. iOS 10 introduced a pair of new settings for simplifying inbox management.
The first tells Mail to arrange emails in a thread in the order they were received, with the most recent ones at the top. The other prompts the app to unify threads by including relevant emails from other mailboxes.
In this tutorial, we're going to teach you how to enable and use Conversation View in Mail and leverage the aforesaid toggles to bring some order to your inbox.