POSTING Bold, Italics, Underline, Colored text, Size options.
Using the size function:

This is the 100% DEFAULT SIZE

This is 125%

This is 150%

This is 200%

You can change the color of the letters using the A  function.  This is RED

I'm presuming that everyone who posts here knows what to do with the B  I  U  ?



The 4 arrows is MAXIMIZE which makes this little box into the full page option so you can see more of what you are posting.

The SOURCE button shows you the background BBCode used by the forum to get the desired appearance.