How to add description to visual for user readability

[SaloniRH]

Can we add a note to a visualization that will show up when the mouse is hoverd over it (or something similar)? Is there any way to automate this task or any inbuilt powerbi future to use Or any API? I don't want a tool tip. I want to add a note about lets say how I calculated something or definition of certain terms or some text that will help explain how to read / interpret the visuzalition. @Expert @User 

[lbendlin]

Something like this?