The best way to install multiple OS (Operating system ) inside a single window is using VM ware Workstation player
This is the best way for those who don’t want to rely on dual boot .
If you have Windows 10 as your main OS of the system . You can install as many number of windows that you need by using the the virtual machine concept of VM Ware.
First download VM ware workjstation player from VM ware website and run the setup for installation. Follow instructions as mentioned in the setup wizard.
After installation is complete . Select free non commercial use if you are an individual that wants to use it for non commercial purposes. If you want to use it for commercial purpose select commercial use and buy licence from VM ware Website.
After that open the VM ware software and select create a virtual machine.
After this provide the .iso file and proceed with the windows installation that you need to install.
For installing windows follow this tutorial
You just have to skip configuring the boot device as shown inside the windows and proceed with the windows installation. Follow the link https://techphenom.com/2018/07/16/how-to-install-windows-10/
and proceed your installation from this image
The procedure to install Windows 7,8,8.1,10 is basically the same.
I hope you have enjoyed the tutorial….If you have any question don’t forget to comment!!