For every ad you put up on Google Ads, you should have an equivalent landing page that is not only relevant to the ad that directs them there, but reinforces the message of that ad. So, if someone clicks on your ad that promises a 30% discount, you cannot send them to a page that talks about a loyalty scheme, for example. Instead, your landing page needs to reinforce that 30% discount in order to convince that user to become a customer.