If you hover your cursor over the bottom of the PDF a control panel will appear. Click on the Save icon. This will open a save dialog window. Navigate to where you want to save the PDF and click Save.

In the PDF tab, there will be a control bar at the top of the screen. click on the download icon. This will open a save dialog box. Make sure that the Save File radio button is active, and then click OK. This will save the PDF to your downloads folder. You can also right click and click Save Page As... this will open a save dialog window. Navigate to where you want to save the file and then click Save.

In the PDF tab, move the cursor to the lower right. A control panel will appear. Click on the Save icon. This will open a Save as window. Navigate to where you want to save the file, and then click Save. You can also open the Save as window by right clicking and clicking Save as.