Google Ads is an online advertising platform developed by Google that allows businesses to create and display ads on Google's search engine results pages (SERPs), as well as on other Google platforms like YouTube and the Google Display Network. It operates on a pay-per-click (PPC) model, where advertisers only pay when a user clicks on their ad.

Bidding in Google Ads refers to the process of setting a maximum amount an advertiser is willing to pay for a click on their ad. Advertisers compete in real-time auctions for ad placements, and the ad with the highest Ad Rank (a combination of bid amount, ad quality, and expected impact of ad extensions) wins the top position. The actual cost per click (CPC) paid by the winning advertiser depends on the bid and the competitiveness of the auction.

Keywords are specific words or phrases that advertisers choose to target in their Google Ads campaigns. These keywords determine when their ads are eligible to appear in search results. Relevant keywords ensure that ads are shown to users who are actively searching for products or services related to those keywords.

Quality Score is a metric used by Google to measure the quality and relevance of an advertiser's keywords, ad copy, and landing page. It ranges from 1 to 10, with higher scores indicating better quality. A higher Quality Score can lead to better ad positions and lower costs per click, as Google rewards ads that provide a positive user experience.

Ad extensions are additional pieces of information that advertisers can include with their ads to provide more context and encourage engagement. These extensions might include additional links, phone numbers, location information, or promotional text. Ad extensions enhance the visibility and effectiveness of ads, leading to higher click-through rates and improved user experience.