Do I need Word for a mail merge?

No. The merge runs in your browser: the document, the data and the results all stay on this device, and the output opens in the Word Editor or downloads as .docx, PDF, a label sheet or .eml drafts.

Where does the data come from?

A CSV or TSV file, an Excel or OpenDocument spreadsheet, a JSON file, or a list you type. The first row is the field names; every field becomes a merge field you can insert.

Can I filter or sort the records?

Yes. Filter on any field (is, contains, greater than, blank and so on), sort by up to two fields, and remove duplicates before the merge runs. The preview shows exactly which records will produce output.

Does it print labels and envelopes?

Yes. Nine Avery stocks (A4 and US Letter) and eight envelope sizes are built in, each as a real document with the stock’s own margins, so the sheet prints where the labels actually are.

Can it send the e-mails?

No, and that is deliberate: sending would mean a server. An e-mail merge writes one .eml draft per record, which Outlook, Thunderbird and Mail open as a ready-to-send draft.

Will Word still re-run my merge?

Yes. Merge fields are saved as real MERGEFIELD fields, so a document exported to .docx can be re-merged in Word against another data source.

Mail Merge Online — Letters, Labels and Envelopes, Free and Private

Merge a spreadsheet or CSV into a Word document: personalised letters, Avery label sheets, envelopes, PDFs and e-mail drafts. Merge fields, rules and an address block per country. Nothing is uploaded.