Windows has a couple different places where you can find different product keys such as the OEM key from vendors such as Dell, Lenovo, etc; and the BackupProductKeyDefault in the registry.

To find the OEM Key you can find your key using this powershell command.

wmic path SoftwareLicensingService get OA3xOriginalProductKey 

or

powershell "(Get-WmiObject -query 'select * from SoftwareLicensingService').OA3xOriginalProductKey"

To find the backup Windows Key in the registry it is located using the regedit path below.

HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform BackupProductKeyDefault

    Option Explicit
    Dim objshell,path,DigitalID, Result
    Set objshell = CreateObject("WScript.Shell")
    'Set registry key path
    Path = "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\"
    'Registry key value
    DigitalID = objshell.RegRead(Path & "DigitalProductId")
    Dim ProductName,ProductID,ProductKey,ProductData
    'Get ProductName, ProductID, ProductKey
    ProductName = "Product Name: " & objshell.RegRead(Path & "ProductName")
    ProductID = "Product ID: " & objshell.RegRead(Path & "ProductID")
    ProductKey = "Installed Key: " & ConvertToKey(DigitalID)
    ProductData = ProductName & vbNewLine & ProductID & vbNewLine & ProductKey
    'Save Data to a file
    Save ProductData
    'Convert binary to chars
    Function ConvertToKey(Key)
    Const KeyOffset = 52
    Dim isWin8, Maps, i, j, Current, KeyOutput, Last, keypart1, insert
    'Check if OS is Windows 8
    isWin8 = (Key(66) \ 6) And 1
    Key(66) = (Key(66) And &HF7) Or ((isWin8 And 2) * 4)
    i = 24
    Maps = "BCDFGHJKMPQRTVWXY2346789"
    Do
    Current= 0
    j = 14
    Do
    Current = Current* 256
    Current = Key(j + KeyOffset) + Current
    Key(j + KeyOffset) = (Current \ 24)
    Current=Current Mod 24
    j = j -1
    Loop While j >= 0
    i = i -1
    KeyOutput = Mid(Maps,Current+ 1, 1) & KeyOutput
    Last = Current
    Loop While i >= 0
 
    If (isWin8 = 1) Then
    keypart1 = Mid(KeyOutput, 2, Last)
    insert = "N"
    KeyOutput = Replace(KeyOutput, keypart1, keypart1 & insert, 2, 1, 0)
    If Last = 0 Then KeyOutput = insert & KeyOutput
    End If
    ConvertToKey = Mid(KeyOutput, 1, 5) & "-" & Mid(KeyOutput, 6, 5) & "-" & Mid(KeyOutput, 11, 5) & "-" & Mid(KeyOutput, 16, 5) & "-" & Mid(KeyOutput, 21, 5)
    End Function
    'Save data to a file
    Function Save(Data)
    Dim fso, fName, txt,objshell,UserName
    Set objshell = CreateObject("wscript.shell")
    fName = ".\ProductKey.txt"
    Set fso = CreateObject("Scripting.FileSystemObject")
    Set txt = fso.CreateTextFile(fName)
    txt.Writeline Data
    txt.Close
    End Function

    start-process -FilePath "CDKey.vbs" -Wait -Passthru 
    $SLS = wmic path SoftwareLicensingService get OA3xOriginalProductKey
    $RLS = Get-ItemPropertyValue 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SoftwareProtectionPlatform' -Name BackupProductKeyDefault
    $SLSKey = $SLS.Split(" ",[System.StringSplitOptions]::RemoveEmptyEntries)
    $DPID = Get-ItemPropertyValue 'HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\DefaultProductKey2' -Name DigitalProductId
    $EditionID = Get-ItemPropertyValue 'HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\DefaultProductKey2' -Name EditionId
 
    function ConvertTo-ProductKey {
    	param (
    		[parameter(Mandatory = $True, Position = 0)]
    		$Registry,
    		[parameter()]
    		[Switch]$x64
    	)
    	begin {
    		$map = "BCDFGHJKMPQRTVWXY2346789"
    	}
    	process {
    		$ProductKey = ""
 
    		$prodkey = $Registry[0x34 .. 0x42]
 
    		for ($i = 24; $i -ge 0; $i--) {
    			$r = 0
    			for ($j = 14; $j -ge 0; $j--) {
    				$r = ($r * 256) -bxor $prodkey[$j]
    				$prodkey[$j] = [math]::Floor([double]($r/24))
    				$r = $r % 24
    			}
    			$ProductKey = $map[$r] + $ProductKey
    			if (($i % 5) -eq 0 -and $i -ne 0) {
    				$ProductKey = "-" + $ProductKey
    			}
    		}
    		$ProductKey
    	}
    }
 
    $x = Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion' -name DigitalProductId
    $key = ConvertTo-ProductKey $x.DigitalProductId
 
    $prodKey = "Windows Backup Product Key Default: $RLS `nOEM Software Licensing Service Key: $SLSKey `nDigital Product ID Windows Key: $key"
 
    Add-Content .\ProductKey.txt $prodKey

The powershell script is run from a bat file which sets the Powershell script bypass for running the powershell script.

    @ECHO OFF
    Powershell.exe -executionpolicy remotesigned -File  ./Get-ProductKey.ps1

https://optionkey.blogspot.com/