How to Filter Your Email on the iPhone
The iPhone has just about everything you will need to manage a busy life, including access to all of your email. It may not take long before your mailbox gets unruly. So as part of iOS 10, Apple added a handy filter button, found at the bottom-left corner of the All Inboxes view or the inbox for a specific account. Using this button, you can easily determine how to filter the emails in your inboxes.
Prior to tapping the button, all the email in your inbox will be readily available. Tap the button, and the iPhone by default will filter the messages so that only those you have not read surface. If you tap the Filtered By link at the bottom of the inbox, you can change the parameter by which mail is filtered.
You can dictate the Mail accounts that are subject to the filter, and choose the criteria in those accounts: flagged mail, mail that is either addressed to you or cc’d to you, mail that has an attachment, or mail from your designated VIP senders.