If someone breaks a law there's police to handle it.
If people need to do research or just watch videos that entertain them.
Shops like Zara or Gucci
To manage the city
Restaurants to eat food or drink and hypermarkets to eat or drink at home.
To live you need to eat and drink.
If someone has a disease or break a leg or an arm... There could be a doctor to help.
If enemies attacked the community they have an army to protect themselves.
If people want to keep their money safe or issue a credit card.
Entertainment like the movies or theme parks.
Schools and houses