Googlebot is the the bot that crawls the internet and collect the information for search rankings. Even if you have never heard of Googlebot this video will help explain how Google collects and decides how to populate search results.
In the second episode of SEO Mythbusting, Martin Splitt (WebMaster Trends Analyst, Google) and his guest Suz Hinton (Cloud Developer Advocate, Microsoft) discuss the many intricacies of Googlebot such as:
What is – and what is not – Googlebot (crawling, indexing, ranking) (1:02)
Does Googlebot behave like a web browser? (3:33)
How often does Googlebot crawl, how much does it crawl, and how much can a server bear? (4:03)
How do you tell that it’s Googlebot visiting your site? (11:12)
The difference between mobile-first indexing and mobile friendliness (12:28)
Quality indicators for ranking (13:35)