http://kb.mozillazine.org/Thunderbird_:_FAQs_:_Using_Templates

Depends on what you want to achieve. '''Option: 1''' If you want to send one generic email to a Mailing List containing several email addresses . Open Write create the email in the same way as normal Save as Template click on 'Templates' folder. Double click on the email in the list to open in a new Write message, modify as required, add the Mailing List to the Bcc field and send. The original Template will remain in the Templates to be reused again and again. Info on Mailing List: * https://support.mozilla.org/en-US/kb/how-create-and-use-mailing-lists-thunderbird '''Option:2''' However, you may prefer to send emails with a more personal touch, so that the names of the contacts are added into a TO field. You would need to use an addon extension called 'Mail Merge' * https://addons.mozilla.org/en-GB/thunderbird/addon/mail-merge/ In order to install a downloaded extension, please do the following: #Click the menu button [[Image:New Fx Menu]] and choose Add-ons. #Drag your downloaded XPI file to the Add-ons Manager tab and drop it. or #Click the menu button [[Image:New Fx Menu]] and choose Add-ons. #Click the gear icon at the top-right corner to the left of the search box and select ''Install Add-on From File…'' #Locate the *.xpi file you downloaded and click ''Open''. #You may need to restart Thunderbird when prompted. For more detailed instructions and information about installing add-ons, see [[Installing an Add-on in Thunderbird]]. In this instance you would need to create a Template that uses the correct format to be able to insert the appropriate names. Open a new Write message Type the correct fields for inserting names. Type rest of email, subject etc. Save as Template. Then open the Template email Modify anything you require like Subject etc. File > Mail Merge See images below to assist in using Mail Merge with Template. I prefer to export the address book as a .csv file and save to suitable folder on desktop. Then I use that file instead of an address book; the .csv file also acts as one of my address book backups. However you could select 'Address Book' and then it will allow to specify which address book to use. note the eg: {{First Name }} used in the Template must match exactly the Column headers for any fields you use. I also prefer to use 'Send Later' option. This will create individual emails and store them in the Outbox, so I can randomly check they are ok before I actually send. There are good instructions on the Mail Merge addon webpage.