How do I sign a PDF online for free without signing up or creating an account?

With PdfDio, you get 5 free document exports every month with zero registration required. Simply drag and drop your PDF, draw or type your signature, and download your signed document instantly. No email, credit card, or account signup is required.

Can I create and add a round company stamp on a PDF?

Yes. PdfDio includes an interactive Company Stamp Maker to generate circular seals, oval stamps, or rectangular boxes complete with Company Name, GSTIN, CIN, and State.

Is it safe to sign and stamp confidential invoices and contracts on PdfDio?

Yes. PdfDio is built on a 100% In-Browser Zero-Upload architecture. All processing runs in browser memory; your documents never leave your device.

PDFDIO Guides & Tutorials

Explore in-depth articles on digital signatures, GST rules, Excel tips, and document privacy.

Is a Stamp or Signature Mandatory on a GST Invoice? What Rule 46(q) Really Says →
The rule asks for a signature, not a stamp. Here is what Rule 46(q) says, when you can skip it, and a quick way to sign and stamp a PDF invoice.
Is It Safe to Upload Contracts and Invoices to Free Online PDF Tools? →
Most online PDF tools send your file to a server. Here is what that means for contracts, statements and ID copies, and a quick way to check any tool before you trust it.
How to Turn a Photo of Your Signature into a Transparent PNG →
A pasted photo of your signature usually drags a grey box along with it. Here is how to take a better photo and strip the paper so only the ink is left.
How to Merge Large PDF Files Without Hitting a Size Limit →
Free PDF mergers often stop at a file size cap. Here is why, how to merge big files in your browser, and how to keep the result small enough to email.
How to Convert PDF to Excel Without Losing Table Formatting →
PDF tables rarely survive a copy and paste. Here is why, how to tell if your PDF will convert cleanly, and five checks to run before you trust the numbers.
Excel to PDF on One Page: How to Stop Columns Spilling onto Page 2 →
You save a report as PDF and half the columns land on page two. Four Excel settings fix it, and a few tricks for sheets that are still too wide.
How to Convert an Image to Excel: Photos of Tables, Bills and Receipts →
Retyping printed tables is slow and error-prone. Here is how photo-to-Excel conversion really works, how to shoot a photo that converts, and what to check after.
Excel Shortcuts Cheat Sheet: 30 Keyboard Shortcuts Worth Learning →
Thirty Excel shortcuts grouped by what you are doing, with Windows and Mac keys, plus fixes for the problems people search for most.
How to Convert PDF to Word Without Scrambled Text or a Broken Layout →
The converted file looks right until you try to edit it. Here is why PDF to Word goes wrong, what converts well, and how to clean up what does not.
How to Convert Word to PDF and Add Your Company Stamp →
Do not email a contract as a .docx. Convert it to PDF, check it, then add your company seal and signature. Here is the short version.
iLovePDF Alternative: Free PDF Tools That Run in Your Browser →
What changes when a PDF tool works on your device instead of a server, an honest look at the trade-offs, and three questions to help you choose.
How to Write Amounts in Words on Invoices and Cheques (INR and USD) →
The words on a cheque outrank the figures if the two differ. Here is how to write amounts in words correctly, with examples in rupees and dollars.
How to Delete Blank Rows in Excel All at Once (Shortcuts, Formulas & Bottom Rows) →
Empty rows break filters, ruin VLOOKUP formulas, and make scrollbars impossible to use. Here are four ways to delete all blank rows in Excel at once, plus the warning everyone forgets.
How to Remove Blank Spaces, Hidden Characters, and Asterisks from AI Text →
Why does text copied from ChatGPT, Claude, or Gemini have weird blank spaces, bold asterisks (*), and invisible zero-width characters? Here is how to clean it for Word, Excel, and publishing.