How to sign a Word document
Word isn't the best format for signing: the text can be changed afterwards. The recommended way is to convert it to PDF and sign it. Here's how.
In 30 seconds
- The simplest way: save the Word file as a PDF and sign it with your finger.
- Inserting an image of your signature in Word is the least secure option: anyone can copy it.
- To sign with a certificate, AutoFirma also signs documents.
The recommended way: save as PDF and sign
- In Word, go to File › Save As (or Export) and choose PDF.
- Open Sign for free and upload that PDF.
- Tap "Add signature", sign with your finger or mouse and place it.
- Download it or send it by email. If someone else has to sign it, choose "Someone else" and you'll get it back signed.
Official figures
of the European eIDAS regulation: a signature cannot be denied validity just because it is electronic.
Inserting an image of your signature in Word
You can insert an image of your signature into the document, but it isn't good practice: anyone can copy it and the document is still editable. Only do it for unimportant documents.
Signing Word with a certificate
If you need a signature with a digital certificate, convert the document to PDF and sign it with AutoFirma.
FAQs
Can I sign a Word document on my phone?
Yes: save it as a PDF (or share it as a PDF from the Word app) and sign it in MultiDocs with your finger.
Why is it better to sign a PDF?
Because a PDF keeps its formatting and, once signed, any change can be detected.
Official sources
- EUR-Lex: Regulation (EU) 910/2014 (eIDAS)
- Government of Spain: AutoFirma downloads (firmaelectronica.gob.es)
We checked each source on 29 October 2026. If you spot an out-of-date figure, write to us at info@multidocs.es.