Copy multiple files

Hi Experts, 

Am trying to copy multiple files in the $finalfile variable but receiving the error '@{FullName = D' doesnot exist'

The script is working well apart from the For Each copy part. Please suggest

function Wait-UdfFileCreation
{ 
 [CmdletBinding()]
        param (
              [string] $path,   # Folder to be monitored
              [string] $file    # File name pattern to wait for.
          )

   $theFile = $path + $file
   $finalfile = Get-ChildItem -Path $theFile | Where-Object length -GT (17000000) | Select-Object -Property FullName 
 While ($true) {

       IF ( $finalfile -ne $null ) {
           #file exists. break loop
           break
       }
       Start-Sleep -s 15
}
        
    

    foreach ($file in $finalfile)
{

Copy-Item $file -Destination "D:\FileLocation\Processing\"

}


    Write-Verbose 'File found.'
}



$rootfolder = "D:\FileLocation\"
$ftppath ="File*.txt"

Wait-UdfFileCreation $rootfolder $ftppath  -Verbose