How to reduce PDF file size on a UMIDIGI phone for email and WhatsApp?

boult

I often scan documents and receipts with my UMIDIGI phone and then need to send them by email or WhatsApp, but the PDFs come out far too large. A multi-page scan from a high-resolution camera can easily reach several MB, and some email apps reject it. What is the best way to reduce PDF file size on this phone without making the text blurry? I’ve tried lowering the scan quality in the camera app, but the results are inconsistent.

So far I’ve found that scanning in black and white or grayscale, using a lower scan resolution (around 150 DPI is usually enough for reading), and cropping the pages before saving all help. I’d also like to know which free apps or settings other UMIDIGI owners use to compress PDFs on Android, and whether the phone’s built-in file manager has any option for it. Please share which method worked for you and roughly how much smaller your files became.