Basically, Google develops algorithms to understand user searches and provide the site that best fits searches.

Google previously called its Algorithms. Penguin, Panda, Hummingbird etc. Ex. As for the Panda 4.2 algorithm, we notice that there are improvements to the content. However, today it prevents naming algorithms, and if the algorithms are large, they are called core updates. These algorithm updates are also officially announced on https://twitter.com/searchliaison account. SEO experts can monitor their work and take action by understanding and interpreting updates based on their fluctuations.

For more detailed information, we can recommend Google source. https://www.google.com/intl/en/search/howsearchworks/algorithms/