A marketing funnel shows, in the shape of a funnel, the stages a customer goes through from first hearing of a brand, to taking an interest and comparing, to buying and coming back.
It is usually split into awareness → interest → consideration → conversion → loyalty, and you improve the points where people drop off at each stage. Startups also often use the AARRR model: acquisition, activation, retention, referral and revenue.
Search and AI answers play a big role at the consideration stage, and landing pages and consultations at the conversion stage.