Incase you don't have Mail setup on your iPad specifically, Apple have posted some instructions which may help: http://www.apple.com/au/support/ipad/assistant/mail/#section_1
Extra Apple Support instructions for a variety of functionality on the iPhone/iPad can be found here: http://www.apple.com/au/support/iphone/mail/
Having a Mail account correctly configured on your device also allows the user to send reports directly from the app, and also help us troubleshoot issues via the Send Diagnostics feature. Send Diagnostics can be accessed via either Settings > Support > "Send Diagnostics" or Settings > About the App > "Send Diagnostics" and then hitting Send. This will send us some diagnostic information to help us troubleshoot the issue.
Please note that in some cases mail can become stuck in the outbox so you may also need to initiate the Send again. If you goto the Outbox and tap the message and then tap the Subject field/line (as if you were to Edit it) then tap the Send button again hopefully this should send the email (provided the correct password settings have all been setup etc, as noted above).