Use your PDF application's Compress, Optimize, or Reduce File Size option and save a copy.
Step by Step
- Keep the original PDF.
- Open the PDF in an application that supports optimization/compression.
- Choose Compress, Optimize, or Reduce File Size.
- Use a moderate quality setting first.
- Save the result as a new file.
- Compare readability and file size before using the compressed copy.
If That Doesn't Work
- Scanned PDFs are often large because every page is an image.
- Aggressive image compression can make small text difficult to read.
- Removing unnecessary embedded images or pages can reduce size without lowering quality.