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Full Mail Merge entry
How-to guide

How to turn on and use Extended Mail Merge

Extended Mail Merge is the supported, server-side version and is enabled by default for most orgs since Summer '17. If it is not already on, a System Administrator can activate it in Salesforce Classic Setup. These steps cover turning the feature on so users can run single and mass merges.

By Dipojjal Chakrabarti · Founder & Editor, Salesforce DictionaryLast updated Jun 16, 2026

Extended Mail Merge is the supported, server-side version and is enabled by default for most orgs since Summer '17. If it is not already on, a System Administrator can activate it in Salesforce Classic Setup. These steps cover turning the feature on so users can run single and mass merges.

  1. Open the Extended Mail Merge setting

    In Salesforce Classic, go to Setup, then User Interface. Under the Advanced area, look for the Activate Extended Mail Merge option.

  2. Turn the feature on

    Select Activate Extended Mail Merge and save. If the option is missing and the feature is not already active, open a case with Salesforce Support from an authorized admin to have it enabled.

  3. Upload Mail Merge templates

    Prepare Word templates in 97-2003 DOC format with merge fields, then upload them in Setup so users can pick them during a merge.

  4. Generate a document

    From a supported record or a list view, choose a Mail Merge template and run the merge. The finished Word file is emailed to you and can be saved to the Documents tab.

Activate Extended Mail Mergeremember

The setting in Classic Setup under User Interface that switches the org from the retired Standard version to the server-side Extended Mail Merge.

Mail Merge templatesremember

Word 97-2003 DOC files uploaded in Setup that hold the merge fields; users select one of these when generating a document.

Document deliveryremember

Extended Mail Merge emails the finished Word file to the user who runs the merge and can also store it on the Documents tab.

Gotchas
  • Mail Merge has no native Lightning Experience UI; users generally run it from Salesforce Classic.
  • Output is Word only. If you need PDF, you must convert manually or use an AppExchange tool or native document generation.
  • A single run is limited to 1,000 records, templates to 1 MB, and a mass merge to roughly 50 MB total.
  • Templates must be saved in the older Word 97-2003 DOC format, and merge field names must exactly match fields on the object.

See the full Mail Merge entry

Mail Merge includes the definition, worked example, deep dive, related terms, and a quiz.