This article explains how to select a flag color and apply it to an email message in the Mail application on a Mac. It also includes information on how to rename the flags. The information in this article pertains to Apple Mail on a Mac with OS X El Capitan (10.11) or later and all macOS versions.

What to Know

  • Open the Mail app on a Mac and select a message or messages.Choose the Flag icon in the Mail toolbar at the top of the screen. Select one of the seven colors for the email.The flag appears in the header of the email and on the mailbox matching that color under Flagged in the left panel.

How to Use Email Flags

One way to organize your Mail messages is to use Mail’s flags. When you mark messages about certain subjects with a colored flag, it’s easy to keep track of them. Apple Mail has seven email flag colors: red, orange, yellow, green, blue, purple, and gray. You may want to flag urgent emails with a red flag, family messages with a blue flag, or work messages with a green flag.

Once you flag a message, Apple Mail adds the flag to the mail header, and it appears in a mailbox of the matching color under Flagged in the sidebar. Here’s how to flag a message.

  • Open the Mail app on your Mac.
  • Select one or more messages.
  • Select the Flag button in the Mail toolbar and choose a flag color.
  • Alternatively, right-click on a message and select a flag color.
  • The chosen flag and color now appears in the header of the selected message.

Renaming Message Flags

You may find it more helpful to name your flags instead of using the default colors. Rename Red to Urgent, for example, or rename blue as Personal. You can even rename a color to Done to indicate that you’ve already taken care of an email. Here’s how to assign names to a colored flag:

Open the Mail app on your Mac.

Select one or more messages.

Select the Flag button in the Mail toolbar and choose a flag color.

Alternatively, right-click on a message and select a flag color.

The chosen flag and color now appears in the header of the selected message.

You must be using more than one flag to show the flags in the mailbox.

  • Open the Mail app.
  • Go to the Flagged mailbox in the Mail sidebar.
  • Select the triangle next to the Flagged mailbox. You’ll see sub-mailboxes labeled with the colored flags you’re using.
  • Select the flag name, select it again, then type a new name. For example, you could name the red flag Urgent.
  • Or, right-click on the name and select Rename, then type your new name.
  • Press Return. You’ve renamed your flagged sub-mailbox. Repeat this to change the name of any of the other sub-mailboxes.

Open the Mail app.

Go to the Flagged mailbox in the Mail sidebar.

Select the triangle next to the Flagged mailbox. You’ll see sub-mailboxes labeled with the colored flags you’re using.

Select the flag name, select it again, then type a new name. For example, you could name the red flag Urgent.

Or, right-click on the name and select Rename, then type your new name.

Press Return. You’ve renamed your flagged sub-mailbox. Repeat this to change the name of any of the other sub-mailboxes.

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