Help Center

Simply drag and drop your PDF file onto the editor, or click the "Open PDF" button to select a file from your computer. PDFox supports PDF files up to 50MB in size.

No! PDFox works without any account or registration. Just open the editor and start working on your PDFs immediately.

PDFox works on all modern browsers including:

• Google Chrome (recommended)
• Mozilla Firefox
• Microsoft Edge
• Safari
• Opera

For best performance, we recommend using the latest version of Chrome or Firefox.

PDFox runs entirely in your browser — your files never leave your device. All processing happens locally on your machine. We never receive, store, or have access to your documents.

Select the "Add Text" tool from the toolbar, then click anywhere on your PDF where you want to add text. Type your content, and use the formatting options to change font, size, and color.

Click the "Signature" tool in the toolbar. You can:

• Draw your signature using your mouse or touchpad
• Type your name and select a signature style
• Upload an image of your signature

Once created, click on the PDF to place your signature. You can resize and reposition it as needed.

Yes! Use the "Edit Text" tool to modify existing text in your PDF. Click on any text element to select it, then edit the content directly. Note: Some PDFs with complex formatting or scanned documents may have limitations.

Our AI-powered OCR (Optical Character Recognition) automatically detects and extracts text from scanned documents and images within your PDF. This makes it possible to edit, search, and copy text from documents that were originally just images.

Click the "Save" or "Download" button in the toolbar. Your edited PDF will be downloaded to your computer. All exports are clean with no watermarks.

Yes — all features are free with no watermarks and no account required. Just open PDFox and start editing your PDFs right away.

Try these solutions:

• Check that your file is a valid PDF (not corrupted)
• Ensure the file is under 50MB
• Try a different browser
• Clear your browser cache and refresh
• Disable browser extensions that might interfere

For better performance:

• Close other browser tabs to free up memory
• Use Chrome or Firefox for best performance
• For large PDFs (50+ pages), be patient during initial loading
• Ensure you have a stable internet connection

PDFox automatically saves your session in your browser. If changes aren't persisting:

• Make sure you're not using incognito/private browsing mode
• Don't clear browser data while working
• Always download your final PDF to save permanently

If fonts appear different, the original PDF may use fonts not available in your browser. PDFox will substitute with the closest matching font. For best results with text editing, use common fonts like Arial, Times New Roman, or Helvetica.

Yes, PDFox V2's DOM-Native PDF Rendering (DNPR) technology is patent-pending under U.S. Patent Application #63/997,982, filed March 6, 2026. This is the first patented approach to rendering PDFs directly to editable DOM elements instead of Canvas pixels.

Yes. After the initial page load, all PDF operations — opening, rendering, editing, and exporting — work without any internet connection. This is architecturally enabled by our patent-pending DNPR engine, which runs entirely in your browser via the patent-pending DNPR engine.