We use "far" and "away" to refer to distance.
- How far is it to the metro station?
- It's not very far. It's not very far away.
- The nearest metro station is about 3 blocks from here. It's 3 blocks away from here.
The comparative and superlative forms are "farther, further" / "farthest, furthest".
- The metro is farther from my house than the bus but it's faster.
"Far" also means much.
"So far" means "up to now".