How can I add contacts to iPad mail

Mail and contacts are two different items. You can always add a contact to your contacts list. But there really isn't a contacts list in the mail utility. However, when you type an email address for the first time, that email address will be remembered the next time you go to type that person an email. For example, if you have never emailed jjohnso@enya.com (fictitious address) once you've entered the email address and sent it, the next time all you would need to type is jj and your iPad will pull up all emails addresses you've written that start with jj.

You can access your contacts in the mail app by - tapping the blue + sign in the To: field when you write an email. The contacts open from the contacts app and you can select one from there. If you tap the Cc/Bcc field you can choose a contact from your contacts as well by the same method.

You can add a contact to the contacts app from an email. When you are reading an email - you can tap on the sender's email address and a window pops up that will allow you to add that contact to the contacts app. You can also add any of the email addresses that may be in the to: field in an email the same way.