In font box use to different and different type of option to change the formatted of the text like to change tha font size,color,type of font family , etc .
Some option of a Font :-
Font Face
This option is used to change the different type of font style.Shortcut key of cut is (Ctrl + Shift + F) .
Select the text or document.
Go to Font face option .
Choose your best font style.
Font size
Font size is used to change the size of font.it shortcut is (ctrl+Shift+P):
Ctrl+Shift+> = Grow Font the Font size
Ctrl+Shift+< = Shrink Font the Font size
Select the text or document.
Go to font size option.
And click on your better size .
Clear Formatting
This option is used to clear the formatting of text.
Select the text or document.
click on Clear Formatting
Bold
Make the selecting text will be Bold.it is used for highlight the text.it shortcut key is (Ctrl + B)
Select the text.
Click on bold option.
Again selecting bold text and click on bold option your text will be unbold.
Italic
Make the selecting text will be Italic.it shortcut key is (Ctrl + I)
Select the text.
Click on Italic option.
Again selecting italic text and click on italic option your text will be unitalic.
Underline
Make the selecting text will be underline.it shortcut key is (Ctrl + u)
Select the text.
Click on underline option.
Again selecting underline text and click on underline option your text will be un-underline.