Paid search, also known as search engine marketing (SEM), is a type of PPC advertising that involves placing ads on search engine results pages. Advertisers bid on keywords related to their business, and when a user searches for those keywords, the ads are eligible to appear in the search results.
Paid search ads can appear above or below the organic search results, and they are marked as ads to differentiate them from the organic results. Advertisers only pay when a user clicks on their ad, hence the name pay-per-click.