settings
currency
the default currency is applied to any amount without one. "use euros from now on", "usa pesos" changes it; amounts that named a currency keep theirs.
name
the name on the web page and on report headers is captured once - the group subject, or your name in a private chat - and never changes on its own (renaming the whatsapp group does nothing). "rename this to house expenses" changes it.
timezone
"yesterday", month boundaries and the dates in reports all depend on where you are. "i'm in mexico city", "timezone madrid" sets it; until then the server's default applies.
language
write in whatever language you like - expenses are understood either way and descriptions are kept as written. replies follow the language of each message; to pin one, "speak english", "en español por favor". teresa replies in english or spanish.