No app to download. No storage space to sacrifice. Open Safari, drop your PDF into ModernPDF, choose your compression level, and save the smaller file. The entire process happens on your iPhone — your document never touches a server.
Navigate to ModernPDF's Compress PDF tool. Tap the file upload area.
Choose your PDF from Files, iCloud Drive, or any other source. The file loads into the browser's local memory.
Select your compression level and tap compress. Save the result back to Files or share it directly via Mail, Messages, or AirDrop.
Modern iPhones support WebAssembly in Safari, which lets ModernPDF run compression algorithms natively in the browser without an app.
Your PDF is processed using your iPhone's own processor. No data is sent to any server — the compression happens in Safari's local runtime.
The compressed file can be saved to Files, shared via AirDrop, or attached to an email directly from the download prompt.
Most PDF compression apps on the App Store require a subscription, show ads, or — worst of all — upload your files to their servers to do the processing. Your iPhone is more than powerful enough to compress a PDF locally. ModernPDF leverages this by running entirely in Safari.
The A-series and M-series chips handle PDF compression in seconds. There is no reason to install a 50MB app, grant it access to your files, and hope it does not phone home with your data.
For sensitive documents on the go — compressing a contract before emailing it, shrinking a scan before uploading it to a portal — the zero-upload approach matters even more on mobile, where you are likely on a shared or public network.
Compress a contract before emailing it from a client meeting. Shrink a report before uploading it from the airport.
Reduce assignment and application file sizes directly from your phone before submission deadlines.
Insurance adjusters, inspectors, and real estate agents who scan and share documents from mobile need quick compression without cloud uploads.
If you are on a shared or public Wi-Fi, uploading files to a compression website is a security risk. ModernPDF keeps your file on your device.
The mobile workflow is straightforward, but here are the specific iOS details:
1. Open Safari and navigate to modernpdf.app/tools/compress-pdf. You can add it to your Home Screen for quick access.
2. Tap the upload area. iOS will show your file picker — browse Files, iCloud Drive, or any connected cloud storage (Dropbox, Google Drive, OneDrive).
3. Select your PDF. It loads into Safari's local memory. You will see a page preview and the current file size.
4. Choose your compression level. For email attachments, medium usually works. For strict upload limits, use maximum.
5. Tap compress. The result appears in seconds with the new file size displayed.
6. Tap download. iOS will prompt you to save to Files or share directly. AirDrop to your Mac, attach to a new email, or save to iCloud Drive for access on other devices.