Every artist who uses canvas uses it differently which means different preparation. One of the more obscure uses is to mount textiles on it. However I am going to talk about how I prep canvas for paint or mixed media.
I buy cheap canvas. My last 30 x 40 cm canvas cost me $AUD5.50, my last 20 x 25 cm cost me $AUD3.50. I start by using gesso (acrylic primer) applied with a roller so it is smooth. The notable exception being Anxiety where I used a palette knife to create a textured background which unfortunately doesn’t show up well in photos.
I then apply antique white (PW6, PY42) with the roller. The picture at the top of the page is called “Society has always been influenced by Queers”. It was painted on the initial layer of antique white. Other times I paint another background over the top of the antique white such as “Aset: Goddess of Sovereignty“.