How do I pass here-string as a parameter to a powershell script in a terminal?

I have a Powershell script named "file1.ps1" as below, which works perfectly fine:

$herestring = @"
State = Defined
FiscalWeek =
"@

$hash = ConvertFrom-StringData $herestring

$hash | Format-Table

This file gives the below output:

PS C:\temp> .\file1.ps1

Name                           Value                                                                                                                                     
----                           -----                                                                                                                                     
State                          Defined                                                                                                                                   
FiscalWeek                                                                                                                                                               

Now, I want to pass $herestring as a parameter to this file. So, the modified script looks like below:

param ($herestring)

$hash = ConvertFrom-StringData $herestring

$hash | Format-Table

So, when I run this in terminal of Powershell ISE or vscode, I am unable to paste or pass the $herestring since it has new line characters.

PS C:\Temp> .\file2.ps1 -herestring 

When I try to paste, each line is being treated as separate command.

PS C:\Temp> .\file2.ps1 -herestring @"
The string is missing the terminator: "@.
At line:0 char:0
PS C:\Temp> State = Defined
State : The term 'State' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was 
included, verify that the path is correct and try again.
At line:1 char:1
+ State = Defined
+ ~~~~~
    + CategoryInfo          : ObjectNotFound: (State:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

PS C:\Temp> FiscalWeek =
FiscalWeek : The term 'FiscalWeek' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path 
was included, verify that the path is correct and try again.
At line:1 char:1
+ FiscalWeek =
+ ~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (FiscalWeek:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException

PS C:\Temp> "@

How do I supply here-string as parameter in this case?

I tried to construct here-string as a single line within single quotes as well as three consecutive double quotes. Also, tried using backtick n and backtick r

Either it leads to syntax error or does not give expected results.

I don't know why your powershell executes at the occurrence of a new line instead of prompting for you to complete the command. It works for me. This is PS 5.1. Maybe update it if its an older version.