How to reduce size of PDF file on Mac

I had some PDF files which were over 14MB in size and I needed a way to reduce the size to upload them to a web site that had a limit of 10MB. I thought this would be an very easy and I would have some option to save the PDF with reduced quality to reduce the size of the file. But I could not find any option on my Mac and found it even more frustrating in Windows 10. One solution I though of, which works is:

1. Open PDF file in Preview.
2. From the 'File' menu select 'Export'.
3. Export the file as a JPEG, this will save the file with a small file size.
4. Open the JPEG in Preview and then from the 'File' menu option select 'Export as PDF'.