You can use these special placeholders in chat, signs, books and in GUIs names.
This is a special placeholder that allows you to move a font image back and forward specifying pixels number.
:offset_-1:
:offset_-2:
:offset_-30:
:offset_25:
As you can see you have to write :offset_AMOUNT: (without spaces).
To actually show make your font image show up you just have to write down its name surrounded by : character
:my_gui:
:blank_menu:
:my_emoji: