Color-code emails in Mail on Mac
You can make email messages easier to spot by color-coding them. For example, give messages with a high priority a red background color. When you use a rule to color-code messages, you can also change the text color.
Manually color-code emails
Go to the Mail app on your Mac.
Select one or more messages in the message list.
Choose Format > Show Colors, then select a color.
Mail changes the background color of the selected messages in the list.
Use a rule to color-code emails
Go to the Mail app on your Mac.
Choose Mail > Settings, then click Rules.
Click Add Rule.
Choose whether any or all of the conditions have to be met.
Click the conditions pop-up menu to set the conditions for color-coding. For example, choose “Priority is high.”
Click the “Perform the following actions” pop-up menus, choose “Set Color of Message,” then choose either “of background” or “of text.”
Choose a color from the pop-up menu, or choose Other and use the Colors window to select a color.
Click OK.
The color-coding is visible only on your Mac; it’s not shown when you look at your messages on other devices.