A standard SMS message can only contain text characters from the GSM alphabet. However, a very widespread practice consists of adding a link (link or URL) in the text of the message, taking advantage of the fact that the vast majority of mobile users have access to the Internet in their devices.
The link can be associated with any resource or multimedia file accessible from the Internet and playable on a mobile device. Some examples would be: websites, landings, images, videos, streaming, pdf, documents, etc. More information at How to send a link or url in an SMS?.
It is important to minimize the weight or memory that linked resources occupy and to check their display on any mobile device. It is recommended to use streaming or optimized viewing platforms such as:
- Videos: Youtube, Vimeo, etc.
- Documents or catalogs: Issuu, Google Drive, etc.
- Forms: Google Forms, TypeForm, etc.