Add Users to Entra ID Group using Graph API

AddUsersToGroup.ps1

# Requires: Microsoft.Graph PowerShell module
# Install (once): Install-Module Microsoft.Graph -Scope CurrentUser

$CsvPath  = "C:\Temp\users.csv"
$GroupId  = "00000000-0000-0000-0000-000000000000"   # <-- Security Group ObjectId

# Connect to Microsoft Graph
# You may be prompted to sign in and consent
Connect-MgGraph -Scopes "Group.ReadWrite.All","User.Read.All"

# Import the CSV
$users = Import-Csv -Path $CsvPath

foreach ($u in $users) {
    $upn = $u.UPN.Trim()

    if ([string]::IsNullOrWhiteSpace($upn)) {
        Write-Warning "Skipping blank UPN row."
        continue
    }

    try {
        # Find the user by UPN
        $user = Get-MgUser -UserId $upn -ErrorAction Stop

        # Add user to the group
        New-MgGroupMemberByRef -GroupId $GroupId -BodyParameter @{
            "@odata.id" = "https://graph.microsoft.com/v1.0/directoryObjects/$($user.Id)"
        } -ErrorAction Stop

        Write-Host "Added: $upn" -ForegroundColor Green
    }
    catch {
        # Common cases: user not found, already a member, permissions, etc.
        Write-Warning "Failed for $upn : $($_.Exception.Message)"
    }
}

Disconnect-MgGraph