To help advertisers know how close they are to getting the top number of potential clicks on their campaigns, Google is rolling out click share metric to search campaigns.
Google stated that the lower your click share, the more opportunity you have to capture additional clicks.
There is a relatively simple process for calculating click share. For example, if your ad is clicked 20 times, but the Google Ads estimates that it could have been clicked 100 times (If you had more extensions, higher bids, or higher budgets), your click share is 20%.