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