As the name suggests this is a technique stitched on canvas or similar foundation material rather than on fabric. It’s counted thread work and its hallmarks are geometric patterns and precision stitching. The most familiar forms of Canvaswork are Tapestry/Needlepoint, Petit Point, Bargello etc.
You can use various kinds of thread and tapestry needles which have blunt ends. The bluntness of the needles stops the thread catching and splitting as you stitch in and out of the canvas.
In depth look at A Summer Parterre
In depth look at Canvaswork cushions