Are you referring to the app or a watch? You posted in the iOS forum.
Each watch got a set number of activities to choose from. The top tier watches got almost all available activities. The lower tier watches just got the basic ones.
"Run" is "Running".
"HIIT" is only available on Venu 2, FR55, FR745, FR945, Fenix 6, Enduro and maybe some more model.
