Learn French: Le présentateur dit qu'il s'agit d'une information importante. - The presenter says that it is about an important piece of news.

The expression il s'agit de translates to "it is about" or "it is a matter of". While c'est just identifies something ("it is"), il s'agit de is used to introduce the core topic or subject of a book, a conversation, or in this case, a news broadcast. Don't forget that it always requires the preposition de.

Can the il in il s'agit change to elle if we are talking about a feminine noun?

No, the il in il s'agit de is strictly impersonal. It works exactly like the "it" in "it is raining" (il pleut). It never changes to agree with anyone or anything, so you will never see elle s'agit or ils s'agissent.

Why is une information translated as "a piece of news"?

In English, "information" and "news" are uncountable nouns, meaning we can't normally say "an information". But in French, une information (often shortened to une info) is countable. It refers to a single fact, a specific news item, or a news report. So, "a piece of news" or "a piece of information" is the most natural English translation.

In English, we could just say "The presenter says it's about...". Can I drop the qu' in French?