Extended Mail Merge
Extended Mail Merge (as well as Mail Merge) is the process of generating form letters for Microsoft Word that are personalized with information from Salesforce. The major conceptual difference between Mail Merge and Extended Mail Merge is that the Mail Merge process will merge Salesforce data into a single Word document and Extended Mail Merge will merge Salesforce data into the same document for many recipients. Think of Extended Mail Merge as being similar to the Mass Email functionality of Salesforce - if you are familiar with that.
Extended Mail Merge is not generally enabled for an organization until after a request is made to the salesforce.com support team. Simply submit a Case with your request and they will enable it for your org. There is no additional cost associated with the request or the functionality and the turn-around time is generally a business day or two.
Once the functionality has been enabled for your org you can make it available to your users by clicking: Setup > Customize (under App Setup) > User Interface. On the resulting screen you will see new options for "Activate Extended Mail Merge" and "Always save Extended Mail Merge documents to the Documents tab" under the portion of the page reading "Advanced." Simply check the box next to these two new options and click the Save button.
With the functionality activated you can now begin to use it.
First you need a mail merge template. Hopefully, you have some already created because you've been using Mail Merge prior to now. If not simply follow the steps outlined in the Mail Merge creation help area: https://na1.salesforce.com/help/doc/en/creating_mail_merge_templates.htm.
Using the Mass Mail Merge Wizard
With Extended Mail Merge, you can easily generate mail merge Word documents—such as form letters with matching envelopes and address labels—for multiple records at the same time.
1. Open the tab home page for accounts, contacts, or leads. Other kinds of records are not currently supported.
2. In the Tools area, click Mass Mail Merge to start the mass mail merge wizard.
3. Choose an appropriate list view from the View drop-down list. To create or edit a list view, see Creating Custom List Views.
4. Select the records to include in the mail merge. To select all records currently displayed on the page, select the checkbox in the column header.
5. Click Next.
6. Select the types of Word documents you would like to generate. The supported document types are documents, envelopes, and labels.
7. Select the Log an activity... checkbox to log the generation of these mail merge documents by adding a completed task on each record.
8. Click Next.
9. Select the appropriate mail merge templates.
~ For documents, choose whether to create one Word document that includes all output or a separate Word document for each record.
10. Optionally, click Preview Template to review a template's contents.
~ Note: that although the Word document that opens may be editable, changes made in Word will not be applied to your current mail merge request.
To make a newly revised template available for mail merge, it must be uploaded first.
11. Click Finish.
Salesforce sends you an email when your generated documents are ready.
They may be attached to the email as either a Word document (.doc) or a Zip file (.zip).
If the attachment size exceeds your organization's maximum allowed email attachment size or if your administrator has set all mail merge documents to be saved to the Documents tab, then your generated documents will be automatically saved on the Documents tab and you will receive an email with a link to their location.