How does PDF compression work?

PDF compression works by:

  • Re-encoding images more efficiently (and sometimes reducing their resolution or color depth)
  • Removing unnecessary data like metadata and unused objects
  • Embedding fonts more efficiently (often by keeping only the characters actually used)
  • Optimizing how the PDF is stored (deduplicating resources and reorganizing internal objects for efficiency)

QuillBot’s Compress PDF tool is free to use and doesn’t add watermarks to your documents.

Read this FAQ: How does PDF compression work?

How do I merge PDF files on Android?

To merge PDF files on Android, you can use an online PDF merger or a dedicated mobile app.

The simplest option is to open a browser on your Android phone and:

  1. Go to a merging tool, like QuillBot’s free merge PDFs
  2. Upload your PDF files
  3. Reorder them as needed
  4. Give your merged PDF a name
  5. Export the merged PDF

This method avoids installing apps and works on any Android device.

Read this FAQ: How do I merge PDF files on Android?

How do I merge PDF files on iPhone?

To merge PDF files on iPhone, the easiest method is to use an online PDF merger in your mobile browser.

Open a browser on your iPhone and:

  1. Go to a PDF merger, like QuillBot’s free PDF combiner
  2. Upload the files from your device or cloud storage
  3. Arrange them in the correct order
  4. Name your new merged document
  5. Download the merged PDF

Read this FAQ: How do I merge PDF files on iPhone?