Get-AADUserId.ps1

[CmdletBinding()]
Param(
    [Parameter(Mandatory, Position = 0)]
    [ValidatePattern('^(?(")(".+?(?<!\\)"@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&''\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$')]
    [String[]]$UserPrincipalName,
    [Parameter(Mandatory, Position = 1)]
    [ValidateScript({Test-Path -Path $_})]
    [String]$FilePath
)
$UserPrincipalName | ForEach-Object {
    try {
        [String]$ID = Get-MgBetaUser -UserId $_ -ErrorAction Stop -ErrorVariable ErrVar | Select-Object -ExpandProperty Id
        "$ID" | Out-File -PSPath $FilePath -Encoding utf8 -Append
        return "$_","$ID" | Format-Table
    }
    catch {
        Write-Error $ErrVar
    }
}