The font size drop-down [] lets you make text larger and smaller. It is the only accessibility compliant way to do so. Please note that while 80% and 90% formats are available, they should be used sparingly if at all, and never on full paragraphs of text.
The formatting buttons [] let you apply Bold, Italics, Strikethrough, Superscript, and Subscript to text. Applying the format a second time will remove it.
The last button in this section [] will remove all superficial stylings from text. It will not remove headings, links, list formats, or other structural formatting from the text.
The alignment drop-down [] lets you left or right align text, or center it.