What kind of ticket you got
Check the top of the notice. Councils and public bodies issue a Penalty Charge Notice under road traffic law. Private companies issue a Parking Charge Notice, which is an invoice.
Airport drop-off charges follow slightly different rules.
Speeding ticket or red light camera?
Those are criminal matters, not civil penalty charges, and they work completely differently. Voidly does not write letters for them, but read this first — the deadline is short and missing it is worse than the offence itself.