Twillo mediaUrl

Hi there,
We would like to send out richtext SMS. Based on my understanding Twillo supported that by using mediaUrl, https://www.twilio.com/docs/sms/api/media-resource
My question : How can we create a richtext SMS url for each message? The url content must be accessible by Twillo.
Thanks
Chun

Can I save the richtext into the database and retrieve the data from a URL?? Can I be done ?