There are 4 locations for characters.
The Upper left is for the Prefecture, which you can select on the page.
The upper right can fit 3 characters A-Z and 0-9.
The Hiragana Symbol can be selected or you can choose to omit the Hiragana symbol which will give you an extra character space in the bottom section.
The Bottom Section can hold 5 Characters, (6 if you drop the Hiragana).
Note: Some of the special Characters are larger than