A free program for Android, by LiveBoard LLC.
LiveBoard: Online Whiteboard is an interactive whiteboard that allows you to draw, visualize ideas, work together, and chat in real-time. It is the most effective tool for visual collaboration.
You can use it to work on projects, brainstorm ideas, solve problems, communicate with other people, and collaborate with your team.
You can also use it to make presentations, write notes, draw diagrams, and more. It is the best tool for teaching and learning.
If you want to record your teaching sessions, you can easily do so. You can share your recordings with your students so that they can use them as references for reviewing.