If you'd like to change the virtual background when giving a lesson, you have several options to choose from:
You can choose to blur your video background from the class pre-checks or from your settings panel inside the classroom:
IMPORTANT: This option is only available when using Chrome as the browser.
You can blur your background from your top panel if you're using Learncube and have an Apple device.
You can do this once in the classroom by going to the window's top right, selecting the video effects block, and then choosing "portrait" on the control centre icon.
A third option would be to change your background using an external video software like ManyCam. (Be aware this app might slow down the class a bit).
As an alternative approach, certain tutors utilize a whiteboard or board containing notes relevant to the topics they teach, making it visible to the students rather than showing their personal surroundings.