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How to sign a PDF document online for free (with legal validity)

Sign contracts, agreements, or forms from your phone or computer without wasting paper, ink, or paying for costly software subscriptions.

Sep 30, 2026
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5 min read
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100% free with no signup
Seguridad

Summary

To sign a PDF without printing, open YAMP Sign PDF, upload your document, and choose how you want to sign: draw with your finger or mouse, type your name using elegant cursive fonts, or upload a photo of your paper signature (the white background is removed automatically). Choose black or blue ink, place it on the page, and download your finished PDF in seconds.

The trouble with printing, signing, and scanning

Signing everyday paperwork should not take half an hour or depend on an office printer. Printing multiple pages, tracking down a pen, signing, taking smartphone photos, and fighting crooked corners or shadows degrades document sharpness and creates huge files that fail to send over email.

Signing digitally saves time and preserves pristine text quality, keeping your documents looking clean and professional.

Is signing a PDF legally valid?

Yes. Across most countries, electronic signatures hold the exact same legal weight as handwritten pen signatures for rental agreements, employment contracts, scopes of work, and everyday commercial transactions.

International law enforces the principle of technological neutrality: courts cannot reject a document or deny its legal validity simply because it was signed electronically.

European Union (eIDAS art. 25)

The eIDAS regulation clearly specifies that an electronic signature shall not be denied legal effect or admissibility in court solely because it is in digital format.

United States (ESIGN & UETA)

The federal ESIGN Act ensures that no contract, record, or signature may be invalidated simply because it was generated or executed electronically.

Latin America & Global

Statutes such as Mexico's Commercial Code, Peru's Law 27269, and Colombia's Law 527 grant full legal backing and evidentiary weight to electronic signatures.

The few exceptions are transactions specifically requiring in-person notarization by law, such as real estate deed transfers or formal wills. For practically everything else, electronic signing is fully binding.

How the security seal works (SHA-256 hash)

How do you prove nobody altered the agreement after you signed it? When signing in YAMP, you can enable an optional audit certificate with a cryptographic SHA-256 hash.

This hash is a unique mathematical fingerprint computed from the exact content of the file. If someone attempts to modify even a single comma, digit, or word afterward, the hash changes completely, exposing any tampering immediately.

Three ways to sign in YAMP

The tool lets you choose the method that best fits your workflow, plus black or institutional blue ink:

Draw with your finger or mouse

Smooth touch and mouse drawing canvas with quick reset to capture your natural signature on phones, tablets, or computers.

Type your name with cursive calligraphy

Type your name to instantly generate a formal, stylized digital signature in cursive or serif typography.

Upload a photo of your paper signature

Sign a blank piece of paper and snap a photo. YAMP automatically wipes out the paper background and shadows, keeping only clean, transparent ink strokes.

Steps to sign your PDF

  1. 1

    Upload your PDF file

    Drag your document into the tool or pick it from your device storage.

  2. 2

    Create or add your signature

    Choose to draw, type, or upload an image. Pick between black or formal blue ink.

  3. 3

    Position it on the page

    Drag your signature to the designated line and resize it to match the layout. Place it on multiple pages if needed.

  4. 4

    Download the finished document

    Click 'Finish and Download' to save your signed PDF instantly, with an optional SHA-256 audit page.

YAMP vs. DocuSign and Adobe Sign

Services like DocuSign or Adobe charge $15 to $40 every month for basic signing and force you into entering credit card details. With YAMP, you sign for free, require no signup, and keep your files private inside your own browser.

FeatureYAMPDocuSign / Adobe
PriceFree$15 to $40 / month
Mandatory signupNot requiredCredit card required
Black or blue ink choiceIncludedBlack only by default
Paper background removalAutomaticNot supported
SHA-256 hash certificateIncluded (optional)Enterprise tiers only
Document privacyProcessed in browserStored on their servers
Free & no signup

Have a document ready to sign?

Upload your PDF now, place your signature in seconds, and download your legally valid document.

Sign PDF for free

Frequently asked questions

Is signing a PDF legally valid?▾

Yes. With the exception of specific notarized deeds (like real estate purchases or formal wills), laws across the EU, US, and Latin America grant standard electronic signatures full legal enforceability for everyday contracts.

How do I remove the background when photographing my signature?▾

You do not need photo editing software. When you upload a picture of your paper signature, YAMP detects the white background and erases it automatically, leaving clean ink lines with transparency.

Can I choose between black and blue ink?▾

Yes. When drawing, typing your name, or uploading a photo, you can switch between formal black or institutional blue ink.

Are my contracts stored on your servers?▾

No. The signature stamping process runs locally inside your browser. Your documents and sensitive data are never stored permanently or shared with third parties.

Can I stamp the signature on multiple pages?▾

Yes. Once your signature is loaded, you can drag and stamp it onto as many pages as needed throughout the document.

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