The Selection Tool is used to mark areas for other operations such as copy and paste or transformation. If you want to prevent paint from being applied outside a specific area of the Canvas, you can use a selection as a mask and only apply active paint inside its area.
If you want to change the size, position, or rotation on your ArtRage Canvas, you can use the Transformation Tools. This system allows you to take all or part of a layer, a sticker, or text that you have entered and freely edit these properties. Items that can be transformed are Paint Layers, Text Layers, Sticker Layers, and Stencils.