Learn Portuguese (Portugal): A praia está longe da escola.

The phrase for far from is longe de. Because the word for school is feminine (a escola), the preposition de merges with the word a (the) to make da. You will do this with all location phrases that end in de, like ao lado da escola (next to the school).

Why use está here if a beach doesn't move?

While you might remember that estar is for temporary states, it is also a standard verb used to talk about physical location. For permanent landmarks like a beach or a school, the verb ficar (to be located) is also very common, so A praia fica longe da escola means exactly the same thing.

Do I always have to use de or da after longe?

Only when you specifically name what the object is far from. If you just want to say that the beach is far, you can simply stop after the word and say A praia está longe.

How would I say the beach is near the school?

You would swap longe for perto (near). Just like longe, it pairs with de, so the contraction with the feminine word for school stays exactly the same: A praia está perto da escola.