The Mail app for iOS includes a basic feature to flag emails for later attention. In Mail, unread messages are indicated with a blue dot and flagged messages are indicated with an orange dot. Learn how to flag messages individually or in batches using the Mail app for iOS 12, 11, and later.

Here's how to flag an email as important in iPhone Mail or iPad Mail:

Open the email in the Mail app.

Select the Reply icon and then choose Flag.