I was told skin tags caused by hpv are spreadable. if so, how can i tell if its a natural tag or by hpv? i know it isn't a wart, so why can it spread?

Two distinct things: Warts caused by hpv virus are entirely different than skin tags, biopsy (histology of tissue) will easily distinguish one from other besides clinical appearance.

Not skin tag: Hpv, or human papilloma virus, causes warts, including common warts and genital warts. These are different from skin tags. A skin tag is generally a flap of skin or similar, while a wart is flat. Because warts contain virus, they can be infectious. To be sure, see your provider.