Is it possible to overlay a p5 canvas over an entire page but still let interaction through?

I want to position a canvas over the entire page allowing me to draw anywhere. Is this possible and/or is this the best approach?

More details, please.

What does “over an entire page” mean? Do you mean you want to display your web browser tab in fullScreen? Or are you developing a p5.js sketch that is running somewhere other than a web browser? Is your goal for the sketch size to be adaptive to the size of different browsers / displays? Do you want it to change size if the browser window changes?