FX options work like equity options with one twist: every call is simultaneously a put. A call on EUR/USD is the right to buy euros and sell dollars, which is identical to a put on dollars against euros, so desks specify both legs.
They are quoted in implied-volatility rather than price, and structured products such as risk reversals reveal whether the market is paying more to protect against a rise or a fall. Large option barriers near round numbers can anchor spot, because dealers hedging them buy weakness and sell strength.
Example: a EUR 10,000,000 three-month call struck at 1.1000 with spot at 1.0840 costs 0.9% of notional, about EUR 90,000. It breaks even at 1.1099.
Related: implied-volatility, big-figure, call-option