Screenplay format exists for one reason: so a stranger — a director, a producer, a first AD — can pick up your script and know exactly what they're looking at without asking you a single question. Get it right and the format disappears. Get it wrong and it's the only thing anyone notices.
The slugline
Every scene opens with a slugline, in caps, telling the reader three things: interior or exterior, the location, and the time of day.
INT. BUS STOP — DAY
That's it. No more detail belongs here — save it for the action line underneath.
Action lines
Action lines describe what we see and hear, written in present tense, kept lean. A good rule: if it can't be filmed or heard, it doesn't belong in an action line. "She's furious inside" isn't filmable. "She slams the door" is.
Character and dialogue
A character's name appears in caps, centered, above their line of dialogue:
ARJUNNuvvu nannu life loki vachina roju nunchi...
Keep dialogue tight. Real conversation is full of filler; screenplay dialogue almost never is.
Parentheticals — use sparingly
A parenthetical under a character's name gives a quick direction — (quietly),
(to Gani) — for something the dialogue alone won't convey. If you're using one on every line, the
dialogue isn't doing its job.
Why the format matters more than it seems
One page of correctly formatted screenplay reads at roughly one minute of screen time. That's not a coincidence — it's the entire reason the format is standardized the way it is. A script that breaks format breaks that estimate, and with it, every scheduling and budgeting decision downstream.