How to clean a PDF before sharing it (and what you cannot hide)

Before sharing a PDF you can check its properties with PDF Info, overwrite visible metadata fields with Edit Metadata and lock form entries with Flatten PDF. OnCloudPDF has no redaction tool, and covering text with a stamp, a watermark or a crop does not remove it: the original text stays in the file and can still be copied.

Updated October 29, 2026 · Runs in your browser, no upload, no account

Read this first: OnCloudPDF cannot redact

Redaction means permanently removing sensitive content, such as a name, an account number or a paragraph, so that it cannot be recovered. OnCloudPDF does not have a redaction or blackout tool. None of the 35 tools deletes a selected piece of text from a page. If you need true redaction, use software designed for it and then check the output by trying to select, search and copy the hidden area.

This warning exists because several tools look like they could hide something and do not. The next section explains exactly why, using what the code of each tool does.

Why a stamp, watermark or crop does not hide text

Each of the following tools draws something on top of, or around, the existing page. None of them removes what is underneath.

• Add Stamp draws one of six preset words (Confidential, Draft, Approved, Rejected, Copy or Final) as text across the page. The text is drawn at an opacity you choose between 10% and 80%, so what is underneath still shows through, and the original page content is untouched. The page also states it is not a security feature.
• Add Watermark draws your text on every page at a size, opacity and angle you set. Even at 100% opacity it is a line of letters, not a box, so it cannot black out a paragraph, and the text underneath remains in the file. It does not encrypt the PDF or stop copying.
• Crop PDF changes the page's crop box. Content outside it is hidden in most viewers but remains in the file, and software that resets the crop box can bring it back.
• Delete Pages is the one tool that does remove content, but only whole pages: the new file does not contain them, and your original stays unchanged on your device.

Rasterizing tools such as Grayscale PDF, PDF/A, N-up PDF and PDF to Scan turn pages into pictures, which removes the selectable text layer. That is not redaction either: the words are still visible as pixels, only copying them has become harder. Do not rely on it to hide information.

What you can clean with OnCloudPDF

1. Inspect the metadata

Open the file in PDF Info. It shows page count, size, title, author, subject, keywords, creator, producer, creation and modification dates, and the dimensions of the first 10 pages. It changes nothing and downloads nothing. Look for an author name you do not want to disclose, a draft title or a software name that reveals where the document came from.

2. Overwrite visible metadata

Edit Metadata can overwrite Title, Author, Subject, Keywords and Creator. It cannot empty a field: a blank field is ignored, so the old value stays. The workaround is to overwrite the value with other text, such as a single space or a neutral word. Producer is read and written back unchanged, and creation and modification dates cannot be edited. The tool only touches the standard document-information fields; it does not look for XMP metadata or other hidden data, so it is not a full metadata scrubber. Run PDF Info on the result to confirm what changed.

3. Flatten forms

If you are sending a completed form, Flatten PDF converts fillable fields (text boxes, checkboxes, dropdowns) into fixed page content, so the recipient sees your entries and cannot change them by accident. The text stays selectable. Other annotations, such as comments and highlights, are not specifically flattened, so review them in a viewer. A flattened file cannot be filled in again, so keep the original.

4. Remove restrictions you are allowed to remove

Unlock PDF copies the pages of your PDF into a new document without encryption or permission settings. It is not a password cracker and never tries to guess or recover a password. The library it uses cannot decrypt content, so files that are truly encrypted may come out unreadable: always open the result and check every page. Only title, author and subject carry over, and the creator is set to 'OnCloudPDF - Unlocked'; bookmarks, form data and other metadata may be lost. Use it only on files you have the right to modify.

5. Remove pages you do not want to share

Delete Pages and Extract Pages both produce a new PDF with only the pages you want. Use one of them when a whole page, such as an internal note or a price list, should not travel with the document. Then check the new file's page count in PDF Info.

A clean-up routine before sending a PDF

1. Open the file in a viewer and read it as the recipient would, including comments and form fields.
2. Remove whole pages that should not be shared with Delete Pages or Extract Pages.
3. If it is a filled form, run Flatten PDF and keep the original.
4. Check the properties in PDF Info and overwrite author, title or creator values with Edit Metadata if needed.
5. If the content is sensitive, do not rely on covering anything: use proper redaction software, then try to select and search the area before sending.
6. Open the final file once more and verify that it is the version you meant to send.

Which tool removes what

When you need stronger tools

For legal, medical or financial documents, use a tool built for redaction and metadata removal, and verify the result yourself. Browser-based processing, as explained in PDF privacy and online tools, keeps the file on your device while you work, but it does not change what the file contains.

Frequently asked questions