==Do users have to have any particular type of email application?==
No. Bugzilla can send email is sent in plain text, the most compatible mail format on the planet. HTML email is available for people who want it formatted in a more readable fashion. The site admin can choose which format is default, but each user can change it from the default also.
==Does Bugzilla allow data to be imported and exported? (Say, from/to Word or Excel.) ==