I use clip studio to draw my stuff but I want to draw something and print it out on paper but idk how big the canvas has to be.
How big is the paper your wanting to print on?
Depends on your resolution/DPI, but you can use the preset sizes in Clip Studio for a guide.
The "standard" resolution for printing is 300 dpi, so just take the dimensions of your paper and multiply by 300 pixels on each side.
11 height and 8.5 width