(I've generalized the original question as @BrendanW.Sullivan suggests.)
I would appreciate recommendations for a whiteboard app for a tablet using an e-pencil. For me: an iPad, using an Apple pencil. For others, please specify the hardware & OpSys & software.
I just want to be able to draw in colors and erase easily, like a physical whiteboard. The whiteboard will be shown to my (remote) students; I don't need them to also access the whiteboard. Other posted questions seek special capabilities (e.g., LaTeX support). My needs are more basic.
Free would be nice but my school will reimburse me so I can also purchase. What I see online is a bewildering variety of products not easily evaluated.