Tap "More Settings" when adding a new task to customize category settings.
Pre-set categories include "Work", "Study", "Health", and "Home". If you would like to add additional categories, tap the + icon. You can then edit the category's name and select an icon and color to associate with the category. Once your tasks are categorized they will show up as such on the main page of your to-do list. Default categories cannot be edited or deleted.