Extend AD accounts for 6 months in PowerShell via Text file to output new user expiry date into CSV

I have and little command that will extend AD accounts for 6 months (define the date) for each user in a text file:

Get-Content C:\adextensions.txt | Set-ADAccountExpiration -DateTime "09/16/2023"

I was wondering if someone could assist me in creating a script that would automatically set expiry date 6 months from the current date when the command is executed.

I know you could set something like this:

$New_Expiry_Date = [datetime]::Now.addmonths(6)

Something like this:

$New_Expiry_Date = [datetime]::Now.addmonths(6)

Get-Content C:\adextensions.txt | Set-ADAccountExpiration -DateTime $New_Expiry_Date

Also if possible could the results of each user new account expiry date be outputted to a CSV file showing username and expiry date.

I am very basic learner at PowerShell.

UPDATE 1

@Theo I ran your code.

Added Get Credential code:

$cred = Get-Credential

Set-ADAccountExpiration -Credential $cred

$New_Expiry_Date = (get-Date).AddMonths(6).Date  # .Date sets this to midnight
$cred = Get-Credential

# assuming the file holds the SamAccountNames of the users each on its own line
# (or the users DistinguishedName, the SID or the object GUID)
$result = Get-Content -Path 'C:\temp\adextensions.txt' | ForEach-Object {
    Set-ADAccountExpiration -Credential $cred -Identity $_ -DateTime $New_Expiry_Date
    # output an object to collect in variable $result
    [PsCustomObject]@{
        User = $_
        AccountExpires = $New_Expiry_Date
    }
}

# display on screen
$result | Format-Table -AutoSize

# save as csv file
$result | Export-Csv -Path 'C:\temp\AccountExpiryDates.csv' -NoTypeInformation

When I ran the code I got this error message

Seems like it states I don't have the permission to execute the script.

I do get prompted to enter a username and password before the script run, my AD account is domain admin account.

PS C:\Users\Me> $New_Expiry_Date = (get-Date).AddMonths(6).Date  # .Date sets this to midnight
$cred = Get-Credential

# assuming the file holds the SamAccountNames of the users each on its own line
# (or the users DistinguishedName, the SID or the object GUID)
$result = Get-Content -Path 'C:\temp\adextensions.txt' | ForEach-Object {
    Set-ADAccountExpiration -Credential $cred -Identity $_ -DateTime $New_Expiry_Date
    # output an object to collect in variable $result
    [PsCustomObject]@{
        User = $_
        AccountExpires = $New_Expiry_Date
    }
}

# display on screen
$result | Format-Table -AutoSize

# save as csv file
$result | Export-Csv -Path 'C:\temp\AccountExpiryDates.csv' -NoTypeInformation
cmdlet Get-Credential at command pipeline position 1
Supply values for the following parameters:
Set-ADAccountExpiration : Insufficient access rights to perform the operation
At line:7 char:5
+     Set-ADAccountExpiration -Credential $cred -Identity $_ -DateTime $New_Expiry ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (TestUser:ADAccount) [Set-ADAccountExpiration], ADException
    + FullyQualifiedErrorId : ActiveDirectoryServer:8344,Microsoft.ActiveDirectory.Management.Commands.SetADAccountExpiration

Also when I run the original script you provided me (whilst running Windows PowerShell ISE as Administrator) works fine.

Your code looks good to me, but if you want output to say a CSV file, you need to use a loop.

$New_Expiry_Date = (get-Date).AddMonths(6).Date  # .Date sets this to midnight

# assuming the file holds the SamAccountNames of the users each on its own line
# (or the users DistinguishedName, the SID or the object GUID)
$result = Get-Content -Path 'C:\adextensions.txt' | ForEach-Object {
    Set-ADAccountExpiration -Identity $_ -DateTime $New_Expiry_Date
    # output an object to collect in variable $result
    [PsCustomObject]@{
        User = $_
        AccountExpires = $New_Expiry_Date
    }
}

# display on screen
$result | Format-Table -AutoSize

# save as csv file
$result | Export-Csv -Path 'C:\AccountExpiryDates.csv' -NoTypeInformation

^{You may need to add admin credentials using the -Credential parameter on the Set-ADAccountExpiration cmdlet}