How to sign a document from your phone

Your phone is the easiest way to sign: you've got the document in your email or on WhatsApp and you sign with your finger, just like on paper. You don't need to download any app.

MultiDocs team2 min readUpdated on 29 October 2026With official sources

In 30 seconds

  • No apps needed: you sign from Safari or Chrome with your finger.
  • It works with a PDF or with a photo of a paper document.
  • When you're asked to sign by email or WhatsApp, you open the link, sign and get your copy.

Step by step on your phone

  1. Save the document on your phone. If it came by email or WhatsApp, open it and save it to “Files” (iPhone) or “Downloads” (Android). If it's on paper, there's no need: you'll take a photo of it.
  2. Open Sign for free in Safari or Chrome.
  3. Tap “Choose document”. Pick the PDF or, if it's on paper, the option to take a photo.
  4. Tap “Me” and then “Add signature”. A large box opens: sign with your finger and tap “Use this signature”.
  5. Tap where the signature goes on the document and tap “Finish”.
  6. Download it or send it by email. On your phone you can also share it straight to WhatsApp or email.

Official data

96.3%

of people in Spain 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

Tips for a good signature with your finger

  • Turn your phone sideways if you want more room for your signature.
  • Sign with your fingertip, slowly and without lifting it too much.
  • If you don't like how it came out, tap “Clear” and do it again: nothing is saved until you tap “Use this signature”.

If you've been asked to sign by email

When someone sends you a document with MultiDocs, you get an email with a big “Review and sign” button. Tapping it opens the document on your phone. If you're asked for details (name, DNI, date…), you type them at the top, in large text; then you tap “Sign”, sign with your finger and you're done. You don't have to sign up, and a signed copy is sent to your email.

Doing it from a computer? See how to sign a PDF.

Frequently asked questions

Do I need an app to sign on my phone?

No. You sign from the browser (Safari on iPhone, Chrome on Android).

Does it work on iPhone and Android?

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

Can I sign a photo of a document?

Yes. You can upload a photo (JPG or PNG) and it's turned into a PDF when you sign it.

Official sources

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 If you spot outdated information, email us at info@multidocs.es.

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