Most email limits sit between 10 and 25 MB. If your scan is a pile of full-resolution images, compression helps - but crushing quality first is how invoices become unreadable.
On FiloPDF, run Compress PDF once at a moderate setting and check the new size. If you still need more room, convert photo-heavy pages with PDF to JPG at 150 DPI, then rebuild with Images to PDF.
Keep a copy of the original. Compression is for sharing, not for your archive master.
Related tool: Open compress pdf
