Pay-per-click (PPC) campaigns are a form of online advertising that allows advertisers to pay a fee each time one of their ads is clicked. They typically appear at the top or bottom of a search engine results page (SERP) or on other websites that are part of the advertiser's chosen network.

Here is a general overview of how PPC campaigns work:

1. Keyword research: The advertiser identifies relevant keywords and phrases that they want their ads to appear for when users search for those terms on the search engine.
2. Ad creation: The advertiser creates ads that will appear when users search for the identified keywords. The ads typically include a headline, a description, and a display URL.
3. Bidding: The advertiser sets a maximum bid for each keyword, which is the most they are willing to pay for a click on their ad.
4. Ad auction: When a user searches for one of the advertiser's targeted keywords, an auction is held to determine which ads will appear on the SERP. The ad with the highest bid that also meets the advertiser's quality requirements wins the auction.
5. Ad targeting: The advertiser can target their ads to specific audiences, such as by location, demographics, or interests.
6. Campaign tracking: The advertiser can track the performance of their PPC campaign through analytics tools to see how many clicks and conversions the ads are generating and make adjustments accordingly.
7. Payment: The advertiser pays the search engine every time their ad is clicked, hence the name "pay-per-click".

PPC campaigns can be a cost-effective way for businesses to drive targeted traffic to their website, generate leads, and increase sales. However, it's important to keep in mind that PPC can be a complex and competitive field, and it's important to have a good understanding of the process and the tools to be successful.