PDF guides
How the tools work, what they do to your file, and how to get a clean result.
Are online PDF editors safe? What happens to your file
What an online PDF editor usually does with your document, the questions to ask before uploading, and how a browser-based editor that never uploads works differently.
How to merge PDFs offline in your browser
Combine several PDFs into one file without uploading them. Step-by-step with the Merge PDF tool, how ordering and inserting work, what the limits are, and how to work without a connection.
How to OCR a scanned PDF without uploading it
Make a scanned PDF searchable in your browser. How local OCR works, what the models can read, how to pick Fast or Accurate mode, and how to check the result.
How to redact a PDF properly (and why black boxes leak)
Drawing a black box over text does not remove it. Learn what real PDF redaction does, how the DynaSparks Redact PDF tool deletes content and verifies the output, and how to check a file yourself.
How to sign a PDF without printing it
Add your signature to a PDF in the browser: draw, type or upload it, place and resize it, flatten the file, and understand the difference between a visual signature and a digital certificate.