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An alternative to Word's mail merge
Word's mail merge is free, already installed, and better than its reputation. Most people looking for an alternative have hit one specific wall rather than found it generally lacking. This page is about which wall, and whether you actually need to move.
What Word does well
Personalised message text from a spreadsheet, with proper document formatting and a preview of the merged result. For a personalised letter — printed or emailed — it is genuinely capable, it costs nothing extra, and it is documented everywhere.
If that describes your job, stay where you are. Replacing a working free tool because something newer exists is not an upgrade.
Wall 1 — a different attachment for each person
This is the one almost everybody arrives with. Word's merge has no attachment field. Not a hidden one, not one behind a setting: the capability was never built, because mail merge was designed for printed letters, where an attachment means nothing.
You can attach one file that goes to everybody. You cannot give Maria her invoice and Sam his. For invoices, payslips, statements, certificates and result slips — the documents most people are actually trying to send — that is the whole job, and Word cannot start it.
How per-recipient attachments work covers the three ways round it, macros included.
Wall 2 — Mac, and Outlook on the web
The Word-to-Outlook handoff is a Windows workflow. On Mac it is unreliable, and in Outlook on the web it does not exist. If your team is mixed, or you have moved to the browser, this alone forces the question regardless of attachments.
Wall 3 — you see a document, not the emails
Word previews the merged document. What you cannot easily see is each email as it will arrive: this subject line, this greeting, this attachment, to this address.
That gap matters because merge errors are systematic. A column mapped one position out is wrong for every recipient simultaneously — you do not get a few odd ones to notice, you get two hundred wrong emails or none.
What to move to, and when not to
If you have hit wall 1, the free option is a VBA macro — Windows only, often blocked by IT policy, usually no preview. The paid option is an Outlook add-in. The four options compared lays both out.
Tellmerge is ours. It replaces the Word half of the workflow rather than Outlook: bring a spreadsheet, write the message once with merge fields, point at a filename column and a folder, read the first few assembled messages, send. It runs in Outlook on Windows, Mac and the web, and a row whose file is missing is held back rather than sent empty.
What you give up is Word's document formatting. If you need precise typography and page layout, Word still composes that better than any email body — and in most of these jobs the formatted document is the PDF attachment, which your accounting or payroll system already produced. More on working without Word.
The honest summary.
Same attachment or none, on Windows? Word is free and fine. A different file per person, or you are not on Windows? Word cannot get there, and no setting will change that.