Function

Create a function and return the value

function CombineString () {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory = $true)] $stringIn1,
        [Parameter(Mandatory = $true)] $stringIn2
        )
	
	$newStr = $stringIn1 + " " + $stringIn2

    # To return the value, simply print it
    $newStr
}

$theNewString = CombineString -stringIn1 "Hello" -stringIn2 "World"
Write-Host "The new string is $theNewString"