Do you need an app to sign documents?

Lots of people look for an app to sign documents on their phone. The good news is you don’t need to install anything: you can sign in your phone’s browser, just as you would in an app.

MultiDocs team2 min readUpdated 29 October 2026With official sources

In 30 seconds

  • To sign with your finger you don’t need to install anything: it works in your phone’s browser.
  • You only need an app if you sign with a digital certificate or DNIe (for example, AutoFirma or Cliente @firma móvil).
  • With no downloads, signers finish sooner and don’t give up halfway.

Signing without installing anything

  1. Open multidocs.es/firmar in Safari or Chrome on your phone.
  2. Upload the document or take a photo of it.
  3. Tap “Add signature”, sign with your finger and drag it into place.
  4. Download it, share it on WhatsApp or send it by email.

To keep it handy like an app, tap “Share” on your phone and then “Add to Home Screen”.

Official figures

96.3%

of people aged 16 to 74 used the internet in the last three months.

Source: INE, 2025
94.8%

of people aged 16 to 74 in Spain use instant messaging such as WhatsApp.

Source: Eurostat, 2025

What about signing with a digital certificate?

If a procedure asks you to sign with a certificate or DNIe, there’s a free official AutoFirma app for phones. We explain it in how to sign with AutoFirma.

FAQs

Does it work on iPhone and Android?

Yes, on any phone with an up-to-date browser.

Is it free?

Yes, signing your own documents is free and unlimited.

Official sources

We checked each source on 29 October 2026. If you spot outdated information, write to us at info@multidocs.es.

More guides

Signing documentsHow to sign a PDF document for freeStep by step to sign a PDF online, free and without printing.Signing documentsHow to sign a document on your phoneiPhone or Android, with your finger, no apps.Signing documentsHow to send a document for signature by WhatsAppSend the link by WhatsApp and get it back signed.