Google stores the information gathered from the services and apps associated with your
Google Account within a log known as
Web & App Activity. It allows Google to offer personalized content to users (search results, suggestions, and relevant ads) based on their previous searches.
However, if you'd like to stop Google from collecting information on you, there's a simple way to opt out of this service.

Click
account settings and sign in with your Google account. Next, go to
Control what you share with Google >
Your searches and browsing activity:
Here, you'll find all the tools you require to control you privacy.
Simply toggle the
Your searches and browsing activity switch
Off to opt out of the
Web & App Activity service.
Click on
Manage Activity and you'll be taken to a page titled
Web & App Activity. Click on the
Ellipsis button displayed at the top-right corner and select
Delete options:
This will open a dialogue window titled
Delete Web & App Activity for. You can delete of all your data by selecting
Advanced >
All time and clicking on
Delete:
All your previous searches will be deleted.