Although you can insert multiple images in a post, you can only attach one file to a post. That said, what browser and browser version are you using? If you do not see the "Use rich formatting" link, what happens if you click on the "Reply" pushbutton (before putting anything in the Quick Reply box)?
I have the same problem on this page, I tried clicking reply, got error message, "You must enter a reply, So I clicked Rich text again , ended up at the same page, your comment above was grayed out, but no rich text option? and this note was in < brackets like> I am trying to show you? 012114 Using version 11.09600.16476 IE
RJB Phillips III - Praise the Lord for His Mercy and Grace
I've just tested this in IE11 and I see what RJB sees, although if I click quote as part of the reply it does appear in the Description box. This box is essentially useless as it is way too small to make it usable. It does work OK in Chrome. This reply was done in Chrome.
RJB said: Using version 11.09600.16476 IE
Using version 11.09600.16476 IE
So you are using IE11, that helps. There are some known issues using IE11... they are being looked into and there should be a "fix" for that soon. In the mean time, you may want to add bentley.com to the Compatability View and see if the behavior is more what you expect.