Stop Apps Running in Background (Window 10)
The Background App Manager is another component in Windows 10 taken from Windows Phone and it enables you to pick which apps you need running out of sight. You can discover the Background App Manager in Settings->Privacy->Background apps. In background apps settings, you can kill whichever apps you don’t need running out of sight. This will spare you on data and battery.
You can save documents as PDFs without any third-party software as Windows offer the option to Save as PDF in Print settings window.