JavaFX is a Java toolkit for making GUI applications that run on Windows, MacOS or Linux, and mobile devices. It is the successor to Swing and AWT toolkits and has been part of the OpenJDK project since its release in 2018. To create a JavaFX desktop application from scratch, one needs to set up a Maven project with the necessary dependencies, configure the Java modules, and write the Java code that extends javafx.application.Application and implements the start method. The example application builds an interactive GUI with a label, text fields for phone number and message, and a button to send SMS messages using Twilio's SMS API. After setting up the Twilio account credentials as environment variables, the application sends a message when the button is clicked.