Sign PDF Online Free — Draw or Upload Digital Signature on PDF

Overview: Draw or upload signatures and place them on any PDF page with zero server uploads.

Sign PDF contracts, agreements, and forms in your browser. Draw your signature or upload a transparent PNG signature stamp. All computations and data processing are executed 100% locally on your device using client-side WebAssembly, HTML5 Canvas, and modern Web APIs without uploading files to any external server.

Supported Formats

PDF Signer & Digital Signature Maker supports the following file formats:

  • PDF — client-side processing support.
  • PNG — client-side processing support.
  • JPEG — client-side processing support.

How to Use PDF Signer & Digital Signature Maker in Browser

  1. Upload Document: Upload the PDF document you need to sign.
  2. Create Signature: Draw your signature on the pad or upload a transparent signature image.
  3. Position & Embed: Select target page and adjust placement sliders, then click 'Embed Signature'.

Key Features & Privacy Protections

  • 100% Client-Side Privacy: Zero cloud upload. Your documents, photos, and files never leave your local browser sandbox.
  • Zero Installation: Runs instantly in Chrome, Safari, Firefox, Edge, Android, and iOS browsers.
  • Free Forever: No sign-up, no subscriptions, no ads, and no file size limits.

Frequently Asked Questions (FAQ)

Can I draw with both mouse and touchscreens?

Yes, the signature pad supports desktop mouse drawing as well as smartphone and tablet touch input.

Can I upload an existing signature PNG stamp?

Yes, you can upload transparent PNG or JPEG signature images directly into the tool.

Is my signature stored on your servers?

Never. The signature is rendered directly into the PDF byte stream in your browser memory and never leaves your computer.

Can I change the ink color of the signature?

Yes, switch between classic black and official blue ink with a single click.

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PDF Signer & Digital Signature Maker

100% Private (Client-Side)•Zero Server Upload

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Sign PDF Online Free — Draw or Upload Digital Signature on PDF

Draw or upload signatures and place them on any PDF page with zero server uploads.. Sign PDF contracts, agreements, and forms in your browser. Draw your signature or upload a transparent PNG signature stamp.

What is Sign PDF and what does it do?

The PDF Signer & Digital Signature Maker enables users to sign contracts, agreements, NDAs, and invoices directly in their browser using a mouse, stylus, or finger, or by uploading an existing signature PNG stamp.

Engineered with strict privacy standards, your sensitive legal contracts and private digital signatures are never transmitted over the internet or logged on cloud servers.

  • Draw custom digital signatures with mouse or touchscreen devices with smooth vector stroke smoothing.
  • Upload existing transparent PNG or JPEG signature stamps with automatic aspect ratio preservation.
  • Select ink color between official contract blue (#1d4ed8) and executive black (#0f172a).
  • Position signatures on any page with percentage-based horizontal and vertical coordinate sliders.
  • Embed signature directly into the PDF content stream locally with instant file download.

How does Sign PDF work?

Signature paths drawn on the HTML5 canvas are serialized into an alpha-channel PNG data URL. pdf-lib loads the target PDF document and embeds the PNG raster image into the document resources dictionary.

The signature image is drawn directly onto the selected page content stream at the computed coordinates. The resulting signed PDF is assembled and exported as a local download blob.

100% private: all processing happens locally in your browser using client-side WebAssembly, HTML5 Canvas, and modern Web APIs. Your files are never uploaded to any server.

Who needs Sign PDF?

Freelancers & Contractors

Quickly sign client statements of work, vendor agreements, and non-disclosure agreements without printer hardware.

Real Estate Agents & Tenants

Sign lease agreements, rental applications, and disclosure forms effortlessly on desktop or mobile.

HR & Recruitment Teams

Sign employment offer letters, company policy acknowledgments, and employee onboarding packets securely.

Small Business Owners

Execute purchase orders, supplier invoices, and service contracts with zero subscription fees.

Supported file formats

PDF Signer & Digital Signature Maker processes the following file extensions and data formats directly in your browser:

PDFPNGJPEG

How to use Sign PDF — step by step

  1. 1

    Upload Document

    Upload the PDF document you need to sign.

  2. 2

    Create Signature

    Draw your signature on the pad or upload a transparent signature image.

  3. 3

    Position & Embed

    Select target page and adjust placement sliders, then click 'Embed Signature'.

Frequently asked questions

Can I draw with both mouse and touchscreens?

Yes, the signature pad supports desktop mouse drawing as well as smartphone and tablet touch input.

Can I upload an existing signature PNG stamp?

Yes, you can upload transparent PNG or JPEG signature images directly into the tool.

Is my signature stored on your servers?

Never. The signature is rendered directly into the PDF byte stream in your browser memory and never leaves your computer.

Can I change the ink color of the signature?

Yes, switch between classic black and official blue ink with a single click.

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