Google's search engine suggestions are generated using an algorithm that takes into account the most popular searches, the context of the search and other factors. The algorithm looks at the frequency of searches and the relevance of the query to the user's query. It also takes into account the user's location and language. The algorithm is designed to provide the most relevant and useful suggestions to the user. The suggestions are constantly updated as users search for new terms, helping to provide more accurate results. Google also allows users to customize their search results to better fit their needs.