If you want to create thick textures on your canvas, use Modeling Paste. It's basically marble dust in a medium that is about the consistency of heavy cake frosting. If you know where you want your texture to be, brush it on your canvas then let it dry before you begin painting or you can mix it directly with your paints. It doesn't seem to diminish the intensity of your colors like white paint would unless you use a lot of it. I seldom use it but there are times when it comes in handy. I have paintings I used it on 20 years ago and it still looks as good as the day I applied it. It's not a substitute for using white paint though. If you want a textured white background, either mix white with it or paint white over it. The brand I've been using is Liquitex Modeling Paste.
Watch a video on stretching canvas and using modeling paste.