All examples are correct.

Heya Miguel. 'People use' is the same as 'one' in English - an indefinite construction. It's common in Romance languages ('se' - Spanish, 'si' - Italian, 'on' - French), but rare in English - the passive voice is privileged. That said, you can use either construction in the passive form: 1. 'Bikes are used for moving people...'. 2. 'Bikes are used to move people...'. The gerund ('moving', 'walking', 'eating' etc.) and the infinitive ('to move' etc.) are largely interchangeable as they are both verbal nouns. I personally favour the infinitive generally (and would here as well). I have a suspicion it's more 'correct', but I couldn't formally explain why, and both sound native. Best, Matt

Yes, since the question is to explain what the equipment does, the first set of sentences are better. All of them are correct, though.

The passive voice seems more natural in this context.