Setting DefaultColumnValue using PnP powershell Script with "&&" or " ' " Symbol

To set the default value of a choice column with special characters like "&" in PowerShell, you need to use escape characters. In PowerShell, the escape character is the backtick (`), which can be used to escape special characters.

So, to set the default value of a choice column to "Folder with &", you can modify your script like this:

# Set the Default Value for Content Type Column level 1
ForEach($item in $FolderList1) {
    $defaultValue = "Folder with `&"
    Set-PnPDefaultColumnValues -List $DestinationLibraryName -Value $defaultValue -Folder $item.Name -Field "ClientDocumentCategory"
}

# Set the Default Value for Content Type Column level 2
ForEach($item in $FolderList1) {
    $Level1Folder = $item.Name
    $Level1folderPath = $DestinationLibraryName + "/" + $Level1Folder

    $Level1FolderList = Get-PnPFolderItem -FolderSiteRelativeUrl $Level1folderPath -ItemType Folder

    Foreach($itemLevel1 in $Level1FolderList) {
        $defaultValue = "Folder with `&"
        $ColumnValue = $itemLevel1.Name
        $Path = $Level1folderPath
        $L2FOLDER = $Level1Folder+ "/" + $ColumnValue

        Set-PnPDefaultColumnValues -List $Path -Value $defaultValue -Folder $L2FOLDER -Field "ClientDocumentType"
    }
}

Note that we're using the backtick (`) to escape the "&" character in the default value variable.