The answer to 'how to kill flea' is to use a combination of flea treatment products and thorough cleaning to eliminate fleas in your home. Start by treating your pets with a veterinarian-recommended flea medication or topical treatment. Then, vacuum all carpets, rugs, and upholstered furniture to remove flea eggs and larvae. Wash all bedding and pet beds in hot, soapy water. You can also use an insecticide spray or powder in areas where fleas are present, but be sure to follow the product instructions carefully and ventilate the area well.
It's important to treat your home and pets regularly, as fleas can reproduce quickly. Repeat the treatment process every 2-4 weeks until the flea problem is resolved. If the infestation is severe or you are unable to get it under control, it's best to contact a professional pest control company for assistance.