Charities are organisations which are not connected to the government or any profit making organisation. They tend to be not-for-profit. Charities are also not allowed to be political, so, for example, Amnesty International is not a charity. Charities are funded in different ways e.g. voluntary donation, the National Lottery, jumble sales, and so on.
Charities offer a wide range of services and help a huge range of people, animals and buildings to name a few. They have different ways of working. Some raise money for one-off projects, e.g. help after an earthquake; some have long-term objectives e.g. campaigning for change. They work locally, nationally or globally.