Using Powershell to add values to existing CSV - powershell

Question

I have been battling this for way too long and I hope you can be of assistance.
I have a CSV for which I need to add some values, preferrably with Powershell. I need to add header row and one column with a fixed text value.
My CSV, before anything done to it, looks like this:
contact-email;contact-sms;contact-firstname
test#example.com;[phone];Mike
And I need it to look like this:
contact-email;contact-sms;contact-firstname;order-site
test#example.com;[phone];Mike;Finland
So the last column "order-site" needs to be added and every line in that column should have a value of "Finland".
So far I have written this Powershell script I got off a tutorial:
$file = Import-Csv E:\Raportit\SALES\SALES_TD_S01.csv -Delimiter "`t" -Encoding Default -Header "contact-email;contact-sms;contact-firstname"
foreach($c in $file) {
Add-Member -Input $c -MemberType NoteProperty -Name "order-site" -Value "Finland"
}
$file | Export-Csv -Path "C:\Temp\test.csv" -Encoding Default -NoTypeInformation
But unfortunately, this makes the CSV look like this:
"contact-email;contact-sms;contact-firstname","order-site"
"test#example.com;[phone];Mike","Finland"
For the use case I have for this file, it need to look like the first should-look-like example, without double quotes and columns separated by semicolon (;). The double quotes are OK as long as the output looks like this:
"contact-email;contact-sms;contact-firstname;order-site"
"test#example.com;[phone];Mike;Finland"
I thank you guys so much in advance, I know this is probably a super simple task but I just cannot wrap my head around it to save my life.

Answer 1

if the file HAS headers:
Import-Csv -Path 'E:\Raportit\SALES\SALES_TD_S01.csv' -Delimiter ';' |
Select-Object *, #{Name = 'order-site'; Expression = {'Finland'}} |
Export-Csv -Path "C:\Temp\test.csv" -Delimiter ';' -NoTypeInformation
if the file DOES NOT HAVE headers:
$headers = 'contact-email','contact-sms','contact-firstname'
Import-Csv -Path 'E:\Raportit\SALES\SALES_TD_S01.csv' -Delimiter ';' -Header $headers |
Select-Object *, #{Name = 'order-site'; Expression = {'Finland'}} |
Export-Csv -Path "C:\Temp\test.csv" -Delimiter ';' -NoTypeInformation
CSV Output:
"contact-email";"contact-sms";"contact-firstname";"order-site"
"test#example.com";"[phone]";"Mike";"Finland"