I want to share a secret with you today. This is something I do ALOT being that I own my own vinyl business. I am sure you have seen vinyl decals applied to canvas. Well, if you have attempted it yourself, you might have run into a problem. Trying to get the vinyl to stick. Let me tell you the secret. First take your canvas and lay it on your work space.
Then paint it with the first layer of paint. Acrylic craft paint works wonders. In between coats I place my plate and brush in a Ziploc bag and close it.
Once the second layer of paint is dry take your handy dandy bottle of mod podge. And paint a thin layer of mod podge over the front of the canvas.
Let dry completely. Overnight would be ideal. And then your canvas is ready for your vinyl to be applied. The mod podge gives it the texture to stick to, where the paint just doesn't quite have it. There is no need to apply mod podge to the top of your decal, unless you have the desire. It won't affect it either way.
(I apologize I don't have the finished product to show you. I prepared this canvas for a friend for her daughters wedding and then she finished it up.)