To reduce the size of a PDF with Adobe Acrobat Reader, you need the Pro version of the program. The feature we are going to use is not included in the free version, if you are going to use this program for more than just reading PDF files, you will find yourself limited. You have two ways to save a document with reduced size: one automatic, and another through the PDF optimizer.
How to reduce the size of a PDF automatically
Open the program and the PDF document which size you want to reduce. Then, go to File and click on Reduce file size:
The following window will appear, where you can save the file in the directory that Adobe Acrobat Reader set by default, or select a new one. In this case, we will not change it (otherwise, we would click Choose a different folder, although this is redundant because we can still choose the folder where to save the reduced PDF in the next step). Click on the button that is highlighted in the window:Folder to save the down-sized document
We will then enter the name of the file and save it as usual. Immediately, you will see that a progress bar appears, informing us how the operation is going:Automatic down-sizing progress
The operation will be completed in a short time, so we only have to wait. It is worth noting that the size reduction will not always be drastic, it will not transform a document from several megabytes into something with a few KBs. The size reduction you appreciate may not be excessive, it depends on factors beyond your control (such as whether there are images included in the document or the quality of the document).
How to reduce the size of a document with the PDF optimizer
To use this method, go to File, and then, place the mouse cursor over Save as other:Access to manual down-sizing
Click on Optimized PDF:Access to the PDF optimizer
The following window will appear, where we can further customize which aspects of the PDF will be modified to reduce its size:Options for manual PDF down-sizing
Here, you can reduce the size of your PDF by adjusting the resolution of the images, although this is a more advanced method, and you need to know at least what parameters are being changed. When you have finished, click on OK. A file browser box will appear where you can choose the folder and name to save this reduced file.