This article explains how to add or edit categories in Outlook: add a new color category, assign a color category to an email, and edit available categories in Outlook. Instructions apply to Outlook 2019, 2016, 2013, 2010, and Outlook for Microsoft 365.
Add and filter categories in Outlook
Use categories in Microsoft Outlook to organize all kinds of items, including email messages, contacts, and appointments. When you assign the same color to a group of related items, such as notes, contacts, and messages, you make those items easier to track. If any of your items are related to more than one category, assign more than one color to it.
Outlook comes with a set of default color categories, but you can easily add your own or change the color and name of an existing label. You can even set up keyboard shortcuts that apply categories to flagged items.
To add a new color category in Outlook:
