A click in Google Search Console is counted any time a searcher clicks on one of your URLs from the SERP and is taken to a page outside of Google Search.
An impression in Google Search Console happens whenever that URL appears in a search result for a searcher. A URL can get impressions even when it shows up “below the fold,” meaning a searcher would have to scroll to see the result, regardless of whether or not the searcher scrolled the URL into view.
CTR stands for “click-through rate,” and it’s a metric that tells you how often people who see your URL in search results end up clicking it. To calculate CTR, Google divides your clicks by your impressions. So, for example, if your URL has 1,000 impressions and 100 clicks, your CTR would be 10%.
4. Average Position:
Average position is the numerical order in which Google displays a URL in search results.