add list of users into Global Security Group

Maybe stating the way-too-obvious here, but you're using "$List" as member to add, not "$User".

On closer inspection, you're using the import incorrectly as well.
Either your csv is a real csv with a header row, in which case you need to use the property (column) of the rows you imported, for example "-member $User.DistinguishedName", or you're using a flat file without header, in which case you need to use "Get-Content" instead of "Import-Csv".

hmm, thanks. I changed it to get-content and error changed. I also attached the csv file? did it need to be .txt?
Add-ADGroupMember : Cannot find an object with identity: 'SamAccountName' under: 'DC=xx,DC=xx,DC=local'.
At line:9 char:18
+ add-ADGroupMember <<<<  -identity mytestGroup -member $user
    + CategoryInfo          : ObjectNotFound: (SamAccountName:ADPrincipal) [Add-ADGroupMember], ADIdentityNotFoundException
    + FullyQualifiedErrorId : SetADGroupMember.ValidateMembersParameter,Microsoft.ActiveDirectory.Management.Commands.AddADGroupMember
doc10.docx

@kazum-

Yes, generally you'd want to either paste the contents of the CSV into a code block or attach a .txt or .csv file (office documents can execute macros when downloaded so most experts won't open them.)  You can also use a screenshot (png, jpg, etc)

To echo oBdA:

when you use this line:

forEach ($user in $list)

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You're creating each $user as a row in the CSV.  So you use . and then the column name to reference the field.

For example, if your CSV is:

First,Last,FavoriteColor
John,Test,Blue

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This code would do the following:

$list = import-csv "C:\test\export\userlist.csv"
foreach ($user in $list) {
$output = $user.First + " " + $user.Last + "'s favorite color is " + $user.FavoriteColor + "."
Write-Host $output
}

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Would write "John Test's favorite color is Blue."

thank you for your excellent support gents