How can I sign a PDF online for free?

Upload your PDF to OptaPDF's Sign tool, create your signature using any of our three methods, place it on the document, and download.

Is my electronic signature legally binding?

Yes, electronic signatures are legally recognized in many jurisdictions under ESIGN and eIDAS acts for commercial agreements.

What is the naming rule for signed files?

The signed document is named with '_signed.pdf' appended to the base filename (e.g., x_signed.pdf).

Can I draw my signature on my phone?

Yes, our drawing canvas is touch-sensitive, making it perfect for signing with your finger or stylus on smartphones.

Can I upload a PNG signature with a transparent background?

Yes! Our 'Upload Image' signature option supports PNG and JPG formats, and transparent PNGs look incredibly professional.

Are my signature files saved?

No. Your signature is rendered directly onto the document canvas temporarily, and all files are auto-deleted after 30 minutes. We never store signatures.

Do you add a watermark to signed PDFs?

No, OptaPDF is completely free and adds zero watermarks.

Can I place multiple signatures on the same PDF?

Yes, you can place multiple signature blocks on different pages before finalizing the PDF.

How do you secure the signature from being copied?

Our backend flattens the signature image directly into the PDF rendering layers, making it impossible to separate or copy.

What is the file size limit?

We support PDF uploads up to 50MB.

Sign PDF Online - Free PDF Electronic Signature

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