Demo-CSVMapping.ps1

function Update-SystemType
{
    $Mastercsv = Import-Csv "C:\Windows\Temp\CSV1.csv"
    $Productinfo = Import-Csv "C:\Windows\Temp\CSV2.csv"
    foreach($record in $Mastercsv)
    {
        $SysType = ($Productinfo | where {$_.Code -eq $record.code}).type
        if ([string]::IsNullOrEmpty($SysType))
        {
            $sysType = 'Unknown, due to non-matching code'
        }
        $record.LaptopDesktop = $SysType
    }
    Return, $Mastercsv
}

<#
PS C:\> Update-SystemType | Format-Table

Computer Product       Code   Country Department LaptopDesktop
-------- -------       ----   ------- ---------- -------------
Com1     EliteDesk 705 HP2190 AU      FN         D            
Com2     EliteBook 830 HP1023 AU      IT         L            
Com3     EliteBook 830 HP1023 FR      FN         L            
Com4     Zbook 15U     HP2020 IN      FN         L            
Com5     OptiPlex 3010 DL1721 FR      FN         D  
#>

Update-SystemType | ConvertTo-Csv | Out-File -FilePath "C:\Windows\Temp\CSV3.csv"