This article explains how to use categories to organize messages in Outlook for Microsoft 365, Outlook 2019, Outlook 2016, Outlook 2013, and Outlook 2010.
Add and filter categories in Outlook
If you receive a lot of email messages and need a way to organize them, group your email messages into categories in Outlook. Outlook provides a starter list of categories. Rename these categories to suit your needs and add more categories as needed. Then, when you want to find messages in a category, filter your message list to see categorized emails. There are several ways to clean up and streamline your Outlook inbox:
Assign color categories to related items so you can easily track and sort them.
Open the message in the reading pane or in a separate window. To assign a category to multiple messages, select all the emails in the message list.
