In March 2020, I switched entirely to online tuition via Skype, instead of face-to-face lessons, for all of my teaching.
Skype works well for one-to-one tuition. I am able to use screen sharing or can switch between multiple cameras so students can see me, what I am writing or a shared screen with questions, diagrams or examples. Students are also able to use screen capture to take copies of examples or other information to incorporate into their notes after the lesson. An ipad or other tablet or laptop work well. A desktop with a webcam also seems to be fine for the lessons. While not ideal, a smartphone can also be ok if reasonably large.
My aim has been to provide direct one to one support and guidance to students, in particular, to help them make up for lost time and reduced learning resulting from the Coronavirus pandemic. The benefits of one-to-one tuition become even more important when students have fallen behind.