We DO NOT install Windows versions that did not come with machine or not legally purchased.
Customers should have legally purchased and therefore have the product key if new install.
If OEM machine like Lenovo, HP, and original OS, BIOS/CMOS. Most have a hidden partition to 'Factory Restore' back to what it looked like when first purchased with all software and Windows version for that product installed.
If you are not using the Factor Restore (bypass the OEM 'bloat'), install the same version as listed (usually a sticker outside indicating or when you boot machine). Windows will then get the product key from BIOS/UEFI. If it does not, there is a mismatch or another issue.