Final answer:
Permanent hair color is usually applied using the bowl-and-brush method or with foil.
Step-by-step explanation:
Permanent hair color is typically applied using the bowl-and-brush method or with foil. The foil method involves separating the hair into sections and painting the color onto the hair, then wrapping the colored sections with foil to keep them separate from the rest of the hair. This method allows for more precise application and control over the placement of color.