Assign contexts to tasks in Outlook by doing any of the following:
- Clicking the colorful Categorize button in the Home ribbon bar in the Tasks view.
- In a task list, right click the Categories column (if visible), and select Categories…
- Open the task, click the multi-colored Categorize button at the top of the window.
- Open the task, right click any of the category color bars near the top of the task window.
If you want a brand new context, add it to your Master Category List by clicking that button. Adding categories there (instead of typing them) prevents you from accidentally creating duplicate categories with typos (like Errands and Errand).