Source: http://www.labnol.org/internet/mail-merge-with-attachments/18561/
Mail Merge helps you send personalized letters or email messages to a large group of people with little effort. The basic content of all these messages is similar but each will have information that is specific to the recipient (like their first name and salutation).
Most web email programs don't offer mail merge but you can take the help of Google Docs to create Mail Merge in Gmail. This is a simple Google Docs spreadsheet that reads email addresses from Google Contacts and sends them personalized emails using your own Gmail account.
Mail Merge in Gmail with Attachments
The previous method didn't however support file attachments. That was limiting because if you are sending a marketing related email, you may often want to attach images or even a product brochure, say a PDF or a Word document, with your message.
Well there's a new sheet to overcome that limitation. This is courtesy Kumar Veetrag who enhanced the original Google Docs script and added support for attachments.
Attaching Files to your Email Message
To get started, upload any document or image, that you wish to include with mail merge, to your Google Docs account. Once the upload is complete, make a note of the Document ID (the string highlighted in yellow).
https://docs.google.com/fileview?id=0B9EOfg1w7YqGYjUxM1&hl=en
Now create a copy of the Mail Merge sheet in your Google Docs account. Select the cell F13, press F2 to enter edit mode and paste the Google Docs ID in this cell.
Then simply follow the steps listed in the original tutorial or watch the screencast below to complete your mail merge. This is how your final product will look like.
This article, titled How to Attach Files When Using Mail Merge in Gmail, was originally published at Digital Inspiration under Gmail, Internet.
