Changing color of a part of an object I cannot find a way how to change a color to another, say &quot;yellow&quot; of a quadrangle on the torus surface.
I'm also interested in the possibility of changing an entire concentric circle of quadrangles around the torus to some other specific color.
First make sure you are in 'Display material preview mode'

add new material to the object via '+' button.

Go to edit mode. Select the desired faces.

Select the desired material, click assign.

Done!