Compose and Reply
If you want to make a new message, tap on the New Message icon on the top right of your screen that looks like a pen and a notepad. A new blank email will appear for you to compose your message. Tap in the To, CC and Subject fields to fill those in. Finally, tap on the blank area below to write your email using the on screen keyboard, before pressing the Send button on the top right of the window.
To reply to an email, tap on the Reply/Forward icon on the top right of your screen that looks like a backwards arrow. You can also forward your currently selected email to other people from this menu.
Adding an Attachment
There are two ways to add an attachment to an email.
Firstly, if you open up a new message and hold your finger press in the compose area, a menu will pop up with some options. 'Insert Photo or Video' will let you add any photo or video from your Camera Roll, and 'Add Attachment' will let you access files from your Google Drive if you have the app installed on your iPad.
Secondly, in any app where you see the Share icon you will have the option of sharing to a new email message. This means that if you using Pages to write a word document for example, you can easily include it in a new email message.
To delete an email, tap on the Delete icon on the top right of your screen.
If you accidentally deleted an email, you can press the Mailboxes button on the top left of your screen to view your other folders, such as your Sent, Junk and Trash folders.
To move a message out of your Trash folder, open your messaged in your trash and then tap the Move icon on the top right of your screen that looks like a folder. This will let you choose a folder to move your message to, such as your Inbox.
(With thanks to Peter O'Callaghan)