What does it mean when you send a message n you get a message back saying sent as a text message?

When you receive a message indicating that it was "sent as a text message," it typically means that the original message could not be delivered through the standard messaging app or platform (like iMessage or WhatsApp) and was instead sent using SMS (Short Message Service) as a fallback. This can happen due to poor internet connectivity, the recipient not using the same messaging service, or other technical issues. SMS messages are usually limited in features compared to messaging app communications, such as not supporting multimedia or read receipts.