If you see the personalization search code (see below) included on your site but still cannot see the difference between normal search and personalized search, the personalization configuration must be set up properly before the query (
query.UsingPersonalization) can work.
query = query.UsingPersonalization(searchCriteria.PersonalizationScope)
First, you must purchase the Personalized FIND service, separate from Optimizely Product Recommendations. You must contact your customer service manager (CSM) or account manager to obtain the service.
After purchasing, the service desk team provides the provision, and then the Personalized FIND is enabled in the Personalization Portal, as shown below. From here, you can implement the code and test it.