Where would I make this change?

Sorry for the lateness, here is the screen shot.

What file extensions are allowed for 'upload attachments'? I have tried doc/htm/rtf, and so far they have rejected. I would like to send a screen shot.

I am having a problem with the menu drop-down. When there an image within the length of the drop-down (ie. top of the body content), the drop-down list appears under the image, thus hiding the drop-down option. What can be done to correct this problem?