What are Sitelinks?

Source: Google

What are Sitelinks?
Sitelinks are hyperlinks to website subpages (section or webpage) that appear under certain Google listings in order to help users to navigate quickly to the website, directly from Google search engine result page. Sitelinks first appeared on Google’s SERP in the year of 2005 and were officially announced in 2006.

According to Google, sitelink extensions take users directly to specific webpages on your website with important information a user maybe looking for, for example, a specific product, support page, login, help page or store hours. When a user clicks on a sitelink, he goes directly to what they want to know or buy

How are Sitelinks Generated?
The website owner cannot influence, add or remove any sitelinks as Google adds the sitelinks through its own automated algorithms process.