To change your text size and line heights (spacing between rows of text) select or click into some text, then choose the Aa icon from the top toolbar.
This will launch the text popup.
- Click the + icon next to font size to increase the size of the font
- Click the - icon next to the letter spacing to increasing letter spacing
You can also click into the number value e.g 13px to set an amount.
Margin and padding options are also available.