Learn Hardcore Indonesian: Siapa pun boleh duduk di kursi depan.

It means "anyone" or "whoever." The space is required in standard Indonesian because pun is a particle written separately: siapa pun. You’ll often see siapapun online; it’s common informally, but in formal writing and exams use the spaced form.

How is "siapa pun" different from "siapa saja" and "semua orang"?

siapa pun ≈ "whoever/anyone," emphasizing no restriction.
siapa saja ≈ "anyone/whichever person," very close in meaning, a bit more colloquial/“any-of-them” in feel.
semua orang = "everyone/all people," a blanket statement about all people, not an open invitation. All three can fit here, but nuances differ slightly: Siapa pun/Siapa saja boleh… invites any taker; Semua orang boleh… states a policy applying to everyone.

What does the particle "pun" do, and are there other words like this?

pun turns question words into indefinites: siapa pun (whoever), apa pun (whatever), kapan pun (whenever), di mana pun (wherever). Write pun separately in these. A few fixed words fuse with it, e.g., walaupun, meskipun, bagaimanapun, sekalipun.

Why use "boleh" here and not "bisa" or "dapat"?

boleh expresses permission ("may, is allowed to"). bisa/dapat express ability ("can"). Compare:

Saya boleh duduk di sini. = I’m allowed to sit here.
Saya bisa duduk di sini. = I can (am able to) sit here. For rules/permission, use boleh; for capability, use bisa/dapat.

How would I ask “May I sit in the front seat?” in Indonesian?

You can say:

Boleh saya duduk di kursi depan?
Bolehkah saya duduk di kursi depan? (more formal/polite)
Apakah saya boleh duduk di kursi depan? (explicit question form)

Why is it "duduk di" and not "duduk ke"?

di marks location (at/in/on), while ke marks movement (to/toward). Sitting is a state at a place, so duduk di kursi depan is correct. Use ke with motion verbs: pindah ke kursi depan (move to the front seat).

Does "kursi depan" mean the car’s front seat or just “the chair in front”?

Both are possible by context:

In a vehicle context, kursi depan naturally means “front seat.”
In a room, kursi depan can mean “a seat at the front (row).” If you mean “the chair in front (of me/this),” say kursi di depan. To be crystal clear about a car, say kursi depan mobil.

What’s the difference between "di kursi depan" and "di depan kursi"?

di kursi depan = on/at the front seat (you’re sitting on that seat).
di depan kursi = in front of the chair (you’re standing/sitting in front of a chair, not on it).

Indonesian has no articles; so how do I say “the front seat” vs “a front seat”?

Context usually covers it. To be explicit:

“the front seat”: kursi depan itu (that front seat) or kursi depan if it’s contextually unique.
“a front seat”: just kursi depan; you can add sebuah (sebuah kursi depan) if you must mark singularity, but it’s often unnecessary.

How do I say this more formally?

Use a passive permission verb:

Siapa pun diperbolehkan duduk di kursi depan.
Siapa pun diizinkan duduk di kursi depan. These sound like official policy statements.

How do I say “No one may sit in the front seat”?

Natural options:

Tidak ada yang boleh duduk di kursi depan.
Tak seorang pun boleh duduk di kursi depan. Avoid Siapa pun tidak boleh… unless you’re sure of the context; the two above are clearer.

Can I use "siapa pun" with a following "yang"-clause like English “whoever …”?

Yes. For example: Siapa pun yang duduk di kursi depan harus memakai sabuk pengaman. = Whoever sits in the front seat must wear a seat belt.

How do I talk about multiple front seats or the front section?

Indonesian doesn’t need plural marking, so kursi depan can already mean “front seats.” To be explicit or emphasize plurality/section:

kursi-kursi depan (plural, more literary)
kursi di bagian depan / kursi bagian depan (seats in the front section)

Is there a more inviting way to say this instead of stating permission?

Yes, use silakan to invite: Silakan duduk di kursi depan. That’s like “Please have a seat in the front.” It’s more hospitable than the policy-like boleh.