Okay kiddo, so in Finland they speak two main languages - Finnish and Swedish. This means that many places in Finland have two names - one in Finnish and one in Swedish.
Let's take the capital city, Helsinki, as an example. In Finnish, it is called "Helsinki" but in Swedish, it is called "Helsingfors". Both names mean the same thing and refer to the same place.
Other examples include Turku, which is called "Turku" in Finnish and "Åbo" in Swedish, and Tampere, which is called "Tampere" in Finnish and "Tammerfors" in Swedish.
Sometimes the names can sound really different in the two languages, but they are still referring to the same place. It's important to know both names so that everyone can understand what place you are talking about, no matter which language they speak.
So, that's why many places in Finland have two names - one in Finnish and one in Swedish.