Turn each PDF page into an image so the text can't be selected or copied, and so watermarks and annotations become fixed. Everything happens inside your browser: the file is never uploaded to any server.
When flattening, each page becomes an image: the text is no longer selectable and the file is usually larger than the original.
It rasterizes each page of the PDF and rebuilds the document with those images, preserving the original size of each sheet. The result: the text can no longer be selected, copied or edited, and any watermark or annotation is embedded so that it can't be removed. It is the natural second half of the watermark: first you mark it with the recipient's name, then you flatten it so the stamp can't be taken off. Keep in mind that the text is still legible: flattening makes copying harder, it does not make it impossible.
The process happens entirely in your browser. One: drag or choose the PDF. Two: choose the quality — high for sharper text, standard for a lighter file. Three: press “Flatten PDF”; the tool turns each page into an image and downloads the flattened document, with “flattened” in the file name. Your original PDF is not touched. Depending on the number of pages and the quality, the process takes from a few seconds to a couple of minutes — you'll see the progress page by page.
Flattening turns each page into an image, and that has three concrete effects. The text is no longer selectable: no one can highlight it, copy it and paste it somewhere else. Watermarks and annotations become fixed: since there is no text layer, there is nothing to edit and no stamp to “remove.” And the document looks identical in any viewer, without depending on fonts or forms. Now the honest part, without overselling: flattening makes copying harder, it does not make it impossible. The text is still legible, so someone with an optical character recognition (OCR) program or even a screenshot could extract it again. And it does not encrypt the file. It is a very useful layer of friction, not a lock.
Where this tool shines is paired with the watermark tool. The order matters: first you put the “for the exclusive use of [name]” stamp on the PDF with the recipient's name, and then you flatten it. The result is a document in which the stamp is embedded in the image of each page — impossible to remove by editing the text, because there is no longer any text — and whose content, on top of that, can't be copied. This is exactly the logic with which at Strategium we circulate our interpretations and files: marked with the name of whoever receives them and delivered in a way that discourages forwarding. If you want to understand the full scheme for circulating sensitive information, it is in how to share a confidential document without losing control of it.
Like the watermark tool, this one works entirely on your device: the libraries that read and rebuild the PDF travel inside the page itself, so the file is never uploaded to any server. You can verify it by disconnecting from the internet — once the page has loaded, it keeps working. For a confidential document that is the property that matters: you don't hand your information to a third-party site to “process” it.
These tools protect the paper; at Strategium we take care of what the paper represents: paying what is fair with legal certainty, through tax strategy and planning, wealth protection and defense before the SAT. If you handle documents of this caliber, there are surely tax and wealth decisions worth reviewing. An honest diagnostic is the first step.
Schedule a diagnostic on WhatsApp Add a watermark first →No. The tool runs entirely in your browser with the PDF libraries embedded in the page itself: the file is not sent to any server and never leaves your device, and you can use it offline once the page has loaded.
Yes. When flattening, each page is turned into an image, so there is no longer a text layer that can be selected, copied or edited. This also locks watermarks and annotations in place. Keep in mind that the text is still legible and, with an optical character recognition (OCR) program or a screenshot, someone could extract it again: flattening makes copying harder, it does not make it impossible.
It is usually larger than the original, because the pages become images. The standard quality option reduces the size; high increases it in exchange for sharper text. For documents with few pages the difference is smaller.
Yes, and it is the recommended combination for confidential documents: first you add the watermark with the recipient's name and then you flatten the result. That way the stamp is embedded in the image and can't be removed by editing the text, and the content can no longer be copied either.
Informational, courtesy tool. Flattening a PDF prevents the selection and copying of the text and fixes the overlaid elements, but it does not encrypt the document or prevent its content from being read, captured on screen or reconstructed with optical character recognition. For confidentiality schemes with legal effect, these measures are combined with agreements and delivery controls suited to each case. Full detail is in the Terms of use.