Once you have the Sierra.iso file, you can use it to test the OS on non-Apple hardware or within a safe environment: How to create a macOS Sierra iso installer successfully?

Many sites offer “macOS Sierra ISO” downloads, but these often:

Example command : hdiutil convert /tmp/Sierra.cdr -format UDTO -o /tmp/Sierra.iso . 4. Using the ISO with Virtual Machines

: Seamlessly copy and paste text or images between your Mac and nearby iOS devices.

I notice you're asking for a , likely for use in a virtual machine (VM) on non-Apple hardware (e.g., VMware or VirtualBox on Windows/Linux).

If you have a legitimate Mac, you can: