Currently, you can't change the default categories created, but you can tailor our app to your personal financial goals by creating your own custom sub-categories.
Create a Category
Select Change Category and select the main category that you would like for your custom category to fall under. At the bottom of the categories list will be a blank field for you to enter your new custom category. Select the + icon to the right of your new category to confirm.
Delete a Category
You can delete a custom category by going to Settings, selecting Preferences and then Manage custom categories. Select the bin icon to the right of the category you wish to delete.