I'd like to add a new category.

From the “Other” screen in the app, tap "General Settings" -> “Edit Categories.”

Then, tap “Add New Categories.” Set the name, the icon, and the color and tap “Save” to the bottom to create a new category.

When creating an income category, from the “Other” screen in the app, tap “Edit Categories” and tap “Income” to the top of the screen before tapping “Create New Categories.”