Office 365 (Outlook 2016 | Outlook 2013) - Rename a color category

Color categories are a great way to visually group similar messages, tasks, contacts, or calendar events.

Each category has a generic name, such as Red Category and Blue Category. The first time that you assign a color category to an item, you are prompted to rename the color category. This is your opportunity to choose a category name that is meaningful to you. If you don't set a custom name, don't worry. You can change the name at any time.

1. In any view, click Home.
   
   
2. In the Tags group, click Categorize, and then click All Categories.
   
   
   
   
3. Click a category, and then click Rename. 
   
   
4. Type the new name for the color category, and then press Enter.