Open your Google Account
Go to My Activity
Sign in if prompted
Select Delete activity by
Choose a time range
Choose All time to remove everything
Select the Google products you want to clear
Click Delete
Open Google Search history settings
Turn off Web & App Activity if you do not want future searches saved
Delete browser history in your web browser
Clear cookies and cached data if needed
Repeat on each device where you use Google Search
Check synced devices and signed-in browsers
Remove saved searches from Google autocomplete by clearing activity
Use Incognito or Private browsing for future searches