Well, basically you can use code using strftime. (Help does not seem to display : link )
Each setting belongs to something in site, hence the options.
Normally News is the one showing time > field 1 short date code
Long date f.e example is used in different areas (like profile etc.)
test in field 1 (short) paste: %A %d hereiam %B heriam %Y (save> go to site News>look)
it should display on News something like: Monday 07 hereiam December heriam 2020
would you use (same field) %m-%d-%Y would display like 12-07-2020
Note ! small chars or Capital makes differences.
so 1 field at a time, and only the one you need to change (so long dates/time and short mixed
per used 'item (news/forum etc..) is possible.
Maybe need to mention, old themes could have such in shortcodes, and per language through locales..)