To send an automated greeting card with Twilio SMS, you need a free or paid Twilio account, a Twilio phone number, .NET 8 SDK, and a code editor or IDE. You'll create a messaging service, add a sender, and set up compliance information. Then, you'll write C# code to generate the automated message, including an image if desired. The code uses the Twilio CLI and adds mediaUrl to include the image. You can test and troubleshoot your scheduled SMS by running the program from the developer console and checking the logs in the Twilio Console. If issues arise, you can cancel or retry the automated greeting. Additionally, you can use this tutorial as a starting point for sending automated calls or WhatsApp messages with Twilio.