I was hunting for information on query suggestions for Office 365….query suggestions are handled in two ways:
1: You can upload your own query suggestions through the admin portal
2: SharePoint will dynamical build a list of query suggestions based on previous searches and click throughs:
SharePoint automatically creates a query suggestion when users have clicked a search result for a query at least six times. For example, if users have entered the query word “coffee” and then clicked on a search result six times, then “coffee” automatically becomes a query suggestion.