Powershell - Struggling to copy file from variable location

You are not showing what is in the text file, forcing us to guess, which is not really a good thing relative to trying to help you. So, I am going to assume it's just a list of drive letters or path UNC's, which is really moot since you can pull those dynamically, thus no need for the file.

I don't understand why you are doing this...

Get-Content 'C:\Users\Administrator\Desktop\here\drive4.txt' | 
Out-String

If it is just a text file for reading, why are you piping that anywhere?

You don't need double quotes for this. Single quotes for simple string, double for variable expansion or other specific formatted requirements

$dest = 'C:\Users\Adminstrator\Desktop\here'

Just pass the read directly

Get-Content 'C:\Users\Administrator\Desktop\here\drive4.txt' | 
ForEach {
    "Processing location $($PSItem.FullName)"
    Copy-Item -Path $PSItem.FullName -Destination $dest -Filter 'peruser.vbs' -Recurse -WhatIf
} 

Point of note: You don't need Write-Host to output to the screen, as that is the PowerShell default, as I'll show in my example to follow. Really, except for writing screen text with color, you'd never need to use Write-Host/echo at all, well, there are a few other specific times to use it.

Also of note, regarding Write-Host from the inventor of Monad/PowerShell Jeffery Snover

• http://www.jsnover.com/blog/2013/12/07/write-host-considered-harmful
• https://twitter.com/jsnover/status/727902887183966208
• https://learn.microsoft.com/en-us/powershell/module/Microsoft.PowerShell.Utility/Write-Information?view=powershell-5.1

You also, do not necessarily need both Get-ChildItem and Copy-Item, since both will read the folder tree recursively. As I'll show below. I am using splatting to tighten up the code block for readability.

So, if I demo this just using a drive and folder on my system. And step through a script build out to make sure I am getting what I expect at each step before moving to the next.

Get-PSDrive -PSProvider FileSystem | 
Format-Table -AutoSize
<#
# Results

Name Used (GB) Free (GB) Provider   Root  CurrentLocation
---- --------- --------- --------   ----  ---------------
C       357.48    118.83 FileSystem C:\  Windows\system32
D       114.10    362.71 FileSystem D:\           Scripts
E      1194.00    668.89 FileSystem E:\                  
F      3537.07    188.83 FileSystem F:\                  
G                        FileSystem G:\  
#>

# Validate if there is any content in the destination
Try 
{
    Get-PSDrive -PSProvider FileSystem | 
    Where Name -eq 'D' | 
    ForEach {
        "Processing location $($PSItem.Root) and the contents are as listed."
        (Get-ChildItem -Path 'D:\Temp\here' -Recurse).FullName
    }
}
Catch {Write-Warning -Message 'No content in the destination folder'}
<#
# Results

Processing location D:\ and the contents are as listed.
WARNING: No content in the destination folder
#>

# Show what is on the drive for the source files
Get-PSDrive -PSProvider FileSystem | 
Where Name -eq 'D' | 
ForEach{
    "Processing the location $($PSItem.Root)"
    (Get-ChildItem -Path "$($PSItem.Root)\Temp\book1.csv" -Recurse).FullName
}
<#
# Results

Processing the location D:\
D:\Temp\Source\book1.csv
D:\Temp\book1.csv
#>

<#
# Show what will happen if a Copy files from the source to the destination occurs
Using splatting for readability
#>

Get-PSDrive -PSProvider FileSystem | 
Where Name -eq 'D' | 
ForEach{
    "Processing the location $($PSItem.Root)"
    $CopyItemSplat = @{
        Path        = "$($PSItem.Root)\Temp\book1.csv"  
        Destination = "$($PSItem.Root)\Temp\here" 
        Recurse     = $true
        WhatIf      = $true
    }
}
Copy-Item @CopyItemSplat
<#
# Results

Processing the location D:\
What if: Performing the operation "Copy File" on target "Item: D:\Temp\book1.csv Destination: D:\Temp\here\book1.csv".

If the results are as expected, execute the action
Using splatting for readability
#>

Get-PSDrive -PSProvider FileSystem | 
Where Name -eq 'D' | 
ForEach{
    "Processing the location $($PSItem.Root)"
    $CopyItemSplat = @{
        Path        = "$($PSItem.Root)\Temp\book1.csv"  
        Destination = "$($PSItem.Root)\Temp\here" 
        Recurse     = $true
    }
}
Copy-Item @CopyItemSplat
<#
# Results

Processing the location D:\
#>

# Validate if there is any content in the destination
Try 
{
    Get-PSDrive -PSProvider FileSystem | 
    Where Name -eq 'D' | 
    ForEach {
        "Processing location $($PSItem.Root) and the contents are as listed."
        (Get-ChildItem -Path 'D:\Temp\here' -Recurse).FullName
    }
}
Catch {Write-Warning -Message 'No content in the destination folder'}
<#
# Results

Processing location D:\ and the contents are as listed.
D:\Temp\here\book1.csv
#>