Office 365 (Outlook) - Create and Assign Color Categories to Messages
Color categories are a great way to get organized. Color adds visibility to your Outlook items so you can sort and find what you need.
To assign a color category, do the following:
- For a message in your Inbox or any message list, right-click the message, point to Categorize, and then click a color category.
The first time that you assign a default color category to an item, you'll be prompted to rename the category. You can also change the color of the category and choose a keyboard shortcut.
For the most current and detailed information on creating and assigning color categories, please reference the Microsoft support page here.