This pattern is used when you want to report something that is commonly said or believed by people. It's like saying 'it is said that...' or 'people say that...' in English. You can use it with verbs, adjectives, and nouns.

For verbs and い-adjectives, you just attach と言われている to the plain form. For nouns and な-adjectives, you add だ first, then と言われている. This pattern is often used in news, essays, and formal conversations, but you can also hear it in everyday speech when talking about common knowledge or rumors.

It's a set phrase, so you don't need to change the 'と言われている' part. The subject is usually a general 'people' or 'they', so you don't need to specify who says it. Just state the thing that is said.