In iOS, it's easy to use manual drag and drop to rearrange items on your lists, and also to rearrange categories. Note: if you choose to disable categories, this feature will not work, and all items will be displayed in alphabetical order.
Read the directions below, and watch the GIF to see how it looks.
How to move items:
To move an item, long press on the item (hold your finger on the item for a second), and then drag the item to where you want.
How to rearrange categories:
To rearrange categories, tap the 3 dots in the upper right hand corner, and select Manage Categories. From there, long press on the category (hold your finger for a second) and drag it to the place you want to place that category. Best of all, it will then change the order of the categories on your list!