set up an email blast

Welcome to Apple Support Communities.

Enter the names and email addresses in Address Book.

Create a new Address Book group, and add their names to the group, either by dragging them individually, by highlighting them and using 'New Group from Selection', or by creating a Smart Group based on the contents of an Address Book field (e.g. all of them share an .edu college email address, all work for the same company)

When you want to send them all the same email, simply type the group name into the To: field of a new email message in Mail. In my example below, I've created several 'CCC' groups in Address Book. In Mail, I just start typing ccc in the To: field, and the names of matching groups automatically appear.

Be certain that you know how many identical messages your email provider allows you to send in one batch. Otherwise your 'blast' might be labeled as 'spam', deleted, or cause your email account to be suspended or cancelled.