I guess a towellette is a small towel one make wet before cleaning your face or your hands with it, example before or after eating in an airplane they are often "served" hot and with an odor of lemon! They are very comfortable and makes you feel relaxed and fresh after use.
I realize this is mostly marketing, but "moist towelettes" is probably the preferred term, since it generally refers to those things used on face or hands. "Wipes" is a term generally referred to as those things used as toilet paper, either for babies or adults. Again, just saying what marketing firms call these things.
They are moist little folded "freshner" things you get at hotels and restaurants with a lot of tourists. Sometimes on airplanes too. This was before the age of purell. Now they usually call them wet wipes. But towelettes sound fancier. Like this: https://www.walmart.com/ip/Moist-Towelettes-Lemon-Scented-Individually-Wrapped-1000-Carton/182268469
They are also in the UK. In "The Hitchhiker's Guide to The Galaxy" (the radio series written in the late 70s/early 80s), There was an abandoned spaceport where a plane full of passengers had been kept in suspended animation for 900 years because they were still waiting for their supply of "lemon-soaked paper napkins".¹