How to reduce PDF size on iPhone without an app
iPhone scans come out surprisingly large. You can shrink them from Safari without installing an app and without the file leaving your phone.
Why this happens
The iPhone Notes and Files scanner saves at high resolution and keeps the colour profile, so a few pages can reach 20 MB. That is more than most email and government upload forms accept.
Step by step
- Open Safari on the iPhone and go to the Compress PDF tool.
- Tap Select file and choose the PDF from Files.
- Pick a quality level and start.
- The smaller file downloads straight into Files.
Worth knowing
There is no app to install and the scan never leaves your phone, which matters when the document is an ID or a medical form. The practical size limit is your phone memory, not a server quota.