Location targeting -- Will only show an ad in the area that you specify. This can be a country, a pinned city, a radius, or a zipcode. We usually recommend that you target a radius around your store's address.
Language targeting -- Will only show ads to a user with the browser set to a given language setting.
Keyword targeting -- Ads appear when a user makes a search query that matches or contain a keyword that you set. Usually, these are things like a type or product or a business name, and helps you capture traffic from users who are actively searching for what you're selling.
In-market/affinity targeting -- Ads appear to people that have a certain interest set or have search history that indicate that they're in the market for a certain product. Most often used for display ads.
Remarketing -- Ads appear to users that have already visited your site.
Placement targeting -- Ads appear on sites that you handpick. This is most often used for display ads.