Desmos is available as a web-based application through any Internet browser, as well as in downloadable mobile app form on both Apple and Android devices. Its most attractive feature is that it is free, yet it offers students many of the capabilities of a Texas Instruments graphing calculator, plus the options to save and share graphs and projects. It also includes the option of accessing pre-built simulations of concepts such as linear regression. The touch-screen or mouse-based interactive capabilities make it very user friendly for the generation of students who are familiar with such methods. Desmos is a way that all of my students, regardless of socioeconomic status, can have access to high-quality digital graphing tools. We use it regularly in my classroom for concepts such as solving linear inequality systems, analyzing slope, and visualizing graphed data, and many of my students have also downloaded it or accessed it on personal devices.
The user guide at https://desmos.s3.amazonaws.com/Desmos_User_Guide.pdf offers an overview of many of its capabilities.