Open a spot color palette in CorelDRAW from a company like Pantone. CorelDRAW has a bunch of spot and process color libraries. Pantone has a range of fluorescent spot colors. Apply the spot color to the artwork objects that need to be loudly colorful. Fluorescent colors typically must be commercially output with a printer loaded with a specific fluorescent ink. It's impossible to get loud fluorescent colors from any CMYK color combination. Fluorescent colors are way outside the limited gamut range of CMYK. You can add a fluorescent spot color plate to a black and white printing job or a CMYK process color job. But the print house doing the work must have the capability to output that kind of printing project. Some large format printers have the ability to print special spot colors, like opaque white, metallic inks and even fluorescent colors. But those colors have to be specially loaded into the printer. And they tend to increase the cost of a print job.