They usually appear where there's friction from clothes eg under bras.
I had three for several years; one behind knee, one inside upper arm and one on navel (which midwife offered to "twist off" for me while awaiting birth of DD1. I said don't you think I have enough to to think about at the mo but did regret not letting her do it).
Anyway back to three tags, went to GP, got appt for small ops clinic and young doctor used a sort of electrical tweezer, snipped them off in a trice and cauterised at the same time. Brilliant, took seconds. Absolutely nothing to it.
Am growing another crop now-around bra line-and could do with another go. Will mention it at my next annual thyroid appointment.