The Washington Post reports: [edited]
A new tool called My Activity allows you to view the information Google is stockpiling about you — and delete things you'd rather it forget.
My Activity shows you what Google has saved about your online activities going back as far as Google has been tracking them. You'll probably be prompted to enter your Google password, after this you will see a chronological list of things you've done using Google's services — the searches you've made, videos you've watched on YouTube, and so on (assuming you haven't already used Google's privacy controls to block the collection of certain information).
You can even search through the data trove to look up a specific record or activity Google has saved.
If you don't want Google remembering a particular search, find the record you want to delete, click on the three vertical dots on the right end of the record and select the delete option.
You can also delete things in bulk by clicking on the three dot menu at the top of the timeline, choose "Delete activity by" and selecting a date range to erase on the next page. If you want an entirely blank slate, opt for the "All Time" option.