How to send a document for signature via WhatsApp
Most people read a WhatsApp message before an email. So if you need a signature from a client, a family or an employee, the quickest way is to send them the document via WhatsApp so they can sign it on their phone. Here's how, step by step and for free.
In 30 seconds
- You send the link via WhatsApp; the other person signs with their finger without downloading anything.
- The signed PDF lands in your inbox with a proof of signature (date, time, IP and document fingerprint).
- Almost everyone uses instant messaging now: it's where people reply first.
How it works
WhatsApp doesn't let you sign documents inside the app. What you send via WhatsApp is a personal link: the recipient taps it, the document opens in their browser, they sign it with their finger and you get it back signed. They don't have to install anything or sign up.
Official figures
of people aged 16 to 74 in Spain use instant messaging such as WhatsApp.
of people aged 16 to 74 used the internet in the last three months.
of the European eIDAS regulation: a signature cannot be denied validity just because it is electronic.
Step by step
- Upload the document. Go to Sign for free, upload the PDF (or a photo of the paper) and choose "Someone else".
- Mark where to sign. Tap "Signature" and place the box. If you need details, also add name, ID number, date or an "I agree" tick box.
- Choose WhatsApp. Under "How shall we get it to them?" tick WhatsApp and enter their mobile number. You can add up to 5 people and ask them to sign in order.
- Confirm your email. The first time, we send you a 6-digit code to check the email address is yours. That's where the signed document will arrive.
- Tap the WhatsApp button. WhatsApp opens on your phone with the message and link already written. You just have to tap send.
- Get it back signed. Once they sign, the signed PDF arrives in your inbox with a proof of signature on the last page.
What the signer sees
- A message from you with a link. Tapping it opens the document, in large print.
- If you ask for details, they type them in at the top before signing.
- They tap "Sign", draw their signature with a finger and that's it.
- When they finish, they can download their signed copy.
WhatsApp, email or SMS: which to choose
| SMS | |||
|---|---|---|---|
| Who sends it | You, from your phone | MultiDocs, on your behalf | You, from your phone |
| Best for | Families, private clients, employees | Businesses and formal documents | People who don't use WhatsApp |
| Automatic reminders | No: you remind them | Yes, every 2 days (up to 3) | No |
| Signed copy for the signer | They download it when signing | It arrives by email | They download it when signing |
You can tick several options at once: for example, email and WhatsApp, so it reaches them both ways.
Is a document signed this way valid?
It's a simple electronic signature under the European eIDAS regulation: it cannot be denied legal effect for being electronic. The proof of signature records that the link was sent via WhatsApp to that number, the date and time of signing, the IP address, the browser and the document's digital fingerprint. Bear in mind that with WhatsApp, you are the one checking the number is right. For documents where identity has to be proven with a certificate, see which signature you need.
Tips
- Before sending it, let them know on WhatsApp that a document is on its way: that way they won't be wary of the link.
- Don't forward the link to anyone else: it's personal to the signer.
- If someone is slow to sign, send them the same message again; the link works for 30 days.
FAQs
Is it free to send documents for signature via WhatsApp?
Yes. You get 20 free requests a month, by email, WhatsApp or SMS. If you need more, the MultiDocs plan costs €19 a month with up to 1,000 requests.
Does the signer have to install anything?
No. They open the link in their phone's browser and sign with their finger. They don't have to sign up.
Can you sign inside WhatsApp?
No. WhatsApp is used to deliver the link; the signing happens on the page that opens when they tap it.
Can several people sign?
Yes, up to 5 on the same document, at the same time or in the order you choose. Each one gets their own link.
Official sources
- Eurostat: internet activities, instant messaging (isoc_ci_ac_i), Spain 2025
- INE (Spanish statistics office): ICT equipment and use in households, 2025
- EUR-Lex: Regulation (EU) 910/2014 (eIDAS)
We checked each source on 29 October 2026. If you spot an out-of-date figure, write to us at info@multidocs.es.