How to get free windows discs or downloads

To get free windows ISO files you go to the microsoft website or to these links:
Windows 10: https://www.microsoft.com/en-us/software-download/windows10
Windows 7: https://www.microsoft.com/en-us/software-download/windows7
Windows 8.1: https://www.microsoft.com/en-us/software-download/windows8

Then after you download them you click ISO file or USB (Whatever you choose) I recommend DVD because its going to be reading off of the DVD