A landing page for ads is the page a visitor lands on after clicking an ad. Its job is to deliver on the promise made in the ad and lead the person to an action without unnecessary detours. The most common mistake is directing all traffic to the homepage, where the customer has to search for what the ad had just offered them. A good landing page repeats the wording from the ad, contains a single main action, answers typical questions and concerns, shows the price or at least its range, and loads quickly on mobile too. For campaigns with a limited duration, it is worth preparing a separate page that can be measured independently. Its performance belongs in the campaign evaluation just as much as the cost per click.
See also: Quality Score, Call to action, Conversion Rate.