IPAD - Send Email to Many Contacts

Depending o the method, you could group all the addresses and anything placed in the bcc (blind carbon copy) the recipients will receive but would not be disclosed.

Well you can setup Outlook or Gmail etc
We use the CC option and then add each address into the CC tab. Only needs to be done once.
How to Set Up Contacts for Group Mailing in iOS Mail
http://www.imore.com/how-to-set-up-mail-contacts-calendars-iphone-ipad

Now to setup your current mail to use Gmail or a different account  as an example
Mail might be able to set up other email accounts with your email address and password,
Here's how to
Go to Settings > Mail > Accounts > Add Account.
If you see your email provider, tap it to add your account automatically. If you don't see your email provider, tap Other to add your account manually.
Here's how to>
 set up and sync Apple, Google, Microsoft, and many other accounts right to your iPhone or iPad!
http://www.imore.com/how-to-set-up-mail-contacts-calendars-iphone-ipad

on the ipad main screen unless you grouped open contacts, groups
Add group, then add contacts to the group.

Gush ally, within the settings of mail, contacts, you can enable which mail accounts have access to the iPad contacts...
I.e. You have multiple mail accounts, but the iPad contacts is not available in your preferred account that would be used to email these messages, check whether the iPad contacts are enabled for the email account in question.

you also have the guides I posted  How to Set Up Contacts for Group Mailing in iOS Mail
if your not bothered to manually do it one by one there is an app
The group mail app is designed  for those iPad users who need frequently send Emails to many recipients. With the help of Group Mail HD, you can create and manage groups, and add or remove contacts from created groups. Of course, the most importance is that the iPad app allows you to send a mail to a number of contacts without typing multiple Email addresses.
Group Mail HD iPad App price $1.99
http://iappsin.com/group-mail-hd-ipad-app.htm

You actually will need to use iCloud to create the group and add contacts to it.
See ref: https://support.apple.com/kb/ph2667?locale=en_US