Windows Sandbox is a new feature available beginning with the Windows 10 May 2019 Update (version 1903) designed to run untrusted applications inside a lightweight isolated environment running independently from your main installation.
Technically, Windows Sandbox is a virtual machine created on demand using Microsoft's hypervisor using the same OS image as the one on your machine. However, it's a very lightweight environment of around 100MB, which has been optimized to boot and run faster, its focus is on security, and it works more efficiently using integrated kernel scheduler, virtual graphics, and smart memory management.
Although you can create a virtual machine to accomplish a similar experience, there are some key benefits with Windows Sandbox. For instance, you don't need to spend additional steps creating or downloading a virtual machine. Every time you launch the feature, it runs a new clean installation of Windows 10. When you finish testing an application and close Windows Sandbox, everything gets deleted automatically. Also, using virtualization isolates anything occurring inside the environment from your main installation offering maximum security to test untrusted applications.
Search for Command Prompt and click the top result;
Type the following command and press Enter; systeminfo.exe
Under the "Hyper-V Requirements" section, if "Virtualization Enabled In Firmware" reads Yes, then you can use Windows Sandbox.
If virtualization isn't enabled, you'll need to start your device in its BIOS or UEFI firmware and enable the feature. This process typically requires hitting one of the function keys (F1, F2, F3, F10, or F12), the ESC, or Delete key as soon as you start your computer. However, these settings will vary by manufacturer, and even by computer model. So make sure to check your device manufacturer's support website for more specific instructions.
Enabling Windows Sandbox:
Search for Turn Windows features on or off, and click the top result to open the Windows Features experience;
Check the Windows Sandbox option;
Click the OK button;
Click the Restart now button.
How to use:
Search for Windows Sandbox, right-click the top result, and select the Run as administrator option.
Just wait a few minutes - if it is your first time.