To format your text you can select from a number of the icons as well as the drop down menu of fonts. You can change the size, color, thickness, style, alignment and more. Think of it as a standard text editor such as Microsoft Word or Word Processor. To format your text you can select the styles you want before you start typing or you can highlight your text after you have typed it and then change the style.
When you have completed the text formatting, click the "Save" icon in the top, left corner of the Page Editor.