Please check:
Admin Dashboard>Settings>Reading>Search Engine Visibility>Discourage search engines from indexing this site (It is up to search engines to honor this request.)
In latest versions of WordPress, the robots.txt file is a virtual file that is created by WordPress but only if a robots.txt file has not been manually added to the site root folder.
You can read up on robots.txt files here:
https://support.google.com/webmasters/answer/6062596?hl=en
The first line means any user agent (browser)
The second means not to index any items at root (which is the site).
Again: It is up to search engines to honor this request.
Once you uncheck that checkbox at settings and save that setting, review the robots.txt file and make sure you submit it to Search Engines (such as Google and Bing).
