`Advertiser Cost: The sum of your spend during this period (in retail)

Link Clicks: The number of clicks on links to select destinations or experiences, on or off Facebook-owned properties. Examples: 1) Someone clicks Shop Now on your ad and goes to your website. 2) User clicks on an image or a call-to-action within ad ad that uses the traffic objective. 3) Someone clicks on an URL link in the text description of an ad. 4) Customer clicks on ad formats that take someone into a full-screen experience, such as lead forms, Canvas and collection. 5) Customer clicks to websites and app stores directly from links in the ad on News Feed

Clicks: The metric clicks (all) includes link clicks as well as clicks on other parts of your ad (ex: someone clicks on your Page's name). The following clicks may be measured under clicks all: Link clicks; Post likes, comments or shares; Clicks to a Facebook Page or Instagram profile; Clicks to expand a photo or video to full screen

CTR (LC) (Click Through Rate): How often people click your ad after it's shown to them, which can help determine the effectiveness of your ad. Calculation  [Link Clicks / Impressions]

Conversion:   When someone completes a pre-determined and desired action on your website, like signing up for a newsletter, viewing a particular page,  or buying a product.