This is the H1 style, you should NOT use it in the body of an article. It is used by the system for titles.

This is the H2 style. It is also for titles, but may be used sparringly in articles, only on RARE occasions. H3 is better.

This is the H3 style. You should use this as a large heading in articles.

This is the H4 style. You can use this to highlight sections of text in articles.
This is the H5 style, similar usage to H4, depending on content hierarchy.

This is the BOLD text style.

This is the Italic text style.

BOLD & ITALIC can both be applied. 

This is the centered style.