a reset

gistfile1.txt

param(
    [Parameter(Mandatory=$true)]
    [string]$TenantId,

    [Parameter(Mandatory=$true)]
    [string]$ClientId,

    [Parameter(Mandatory=$true)]
    [string]$ClientSecret,

    [Parameter(Mandatory=$true)]
    [string]$TargetApplicationName,

    [string]$OwnerUserPrincipalName = "firstname.lastname@gmail.com"
)

Install-Module Microsoft.Graph -Scope CurrentUser -Force

$secureSecret = ConvertTo-SecureString $ClientSecret -AsPlainText -Force
$credential = New-Object System.Management.Automation.PSCredential($ClientId, $secureSecret)

Connect-MgGraph -TenantId $TenantId -ClientSecretCredential $credential -NoWelcome

$app = Get-MgApplication -Filter "displayName eq '$TargetApplicationName'"

if (-not $app) {
    throw "No application found with displayName '$TargetApplicationName'"
}

if ($app.Count -gt 1) {
    throw "Multiple applications found with displayName '$TargetApplicationName'. Use AppId/ObjectId instead."
}

$user = Get-MgUser -UserId $OwnerUserPrincipalName

$ownerRef = @{
    "@odata.id" = "https://graph.microsoft.com/v1.0/directoryObjects/$($user.Id)"
}

New-MgApplicationOwnerByRef `
    -ApplicationId $app.Id `
    -BodyParameter $ownerRef

Write-Host "Added $OwnerUserPrincipalName as owner of application '$TargetApplicationName'"