This script allows you to open multiple pdf files simultaneously in edge browser

pdfopener.ps1

$folder = Resolve-Path -Path $args[0]
$files = Get-ChildItem $folder -Filter *.pdf
Write-Host $folder

foreach ($f in $files){
    $fullpath = $f.FullName
    $filepath = -join("file:///", $fullpath) | 
                    ForEach-Object { $_ -replace "/", "\" } | 
                    ForEach-Object { $_ -replace " ", "%20"}
    start msedge $filepath
    #Write-Host $filepath
}