1 First of all, we need to download a free software, as shown in the figure. The browser searches for "adobe acrobat pro" and then installs it on the computer.

2. Then we find the PDF file that needs to be compressed, and right-click to view the properties. As you can see, before compression, the file was 242KB.

3. After opening the file with the newly installed software, click "Document" in the menu bar and click "Optimize scanned PDF".

We save the compressed file as a file with another name. As shown in the figure, we see that the file is obviously smaller.