Free Text is a feature that lets you to type your text and then edit it as you want. (Αs opposed to Auto Text that uses hot spots and auto-shrinks all inserted text accordingly.)
To find this option, go to Card Sets, select a card set you'd like to edit and Add card.
Switch from the default text option Auto Text to Free Text by clicking on the Text button (1).
From here, you can also:
Add text and then select specific words or phrases to make them appear in bold, italics or underlined.
Distribute your text evenly between the margins, align text to the right or left.
Change the font color and highlight text with color.
Select a font from the dropdown list and modify the size.