You're sending emails from your Node.js app with the Twilio SendGrid API, and now you want to attach files to your emails. The Twilio SendGrid API makes it straightforward to include attachments to the emails that you send. You'll need to have a free Twilio SendGrid account, set up environment variables for your API key, install the Twilio Sendgrid Node Library, and use the Node File System API to read and encode your file as a base64 string. Then, create an email message with the attachment property, passing an array of attachment objects or just one single attachment. Finally, send the email using the `send` method of the sgMail object, and verify that it works by checking your inbox.