Blab's default post edit window includes icons above the post edit area.
You can highlight text in your post to format them with bold, italic,
different font colors, and so forth.
Keep in mind that formatting should be done only to help convey your
message, not just to 'play around' with decoration. Blab readers do
not appreciate excessive use of highlighting, etc.
To access more post editing features to insert images, hyperlinks and
so forth, click "More Edit Options" in the lower right frame of your
post edit window. More editing icons will appear above the post edit area.