Hello,
Do you mean this description https://prnt.sc/sNSEU_9U6D5P ? Every product has its own description, to edit it click here – https://gyazo.com/bc06551c429ca8c9189b26ff0d76c71b > https://prnt.sc/jp6JHzAuP4ok
On the demo, all descriptions are the same, but it will be different for real products, so should be edited separately.
Regards