There is no formal "Machine Code Number."
There is a provision in many relatively modern BIOS to allow you to enter a unique number for Asset Management.
The only other instance I have seen is where as part of a copy protection schema you do a two step process. Step one generates a unique machine code or ID. Step 2 requires you enter this value, and then the returned key value (usually through email) from the software vendor.
If that is what is required here, site policies prohibit any further discussion.