1. First open the Adobe Acrobat application, click the file in the menu bar at the top of the screen, click Open ..., select the PDF document to be reduced, and then click the Open button.

2. Click the file in the menu bar at the top of the screen.

3. Then click to reduce the size of the PDF.

4. Then click the "Compatibility:" drop-down menu.

5. Click on the latest version of Acrobat program. Selecting only a few newer versions to open a file can greatly reduce the file size.

6. Then in the window that opens, select the path to save the file.

7. Click Save, and the compressed PDF file will be saved to the computer.