This article explains how to delete your entire Google search history on an Android phone or tablet. If you want to know how to eliminate web browsing activity, read this other article.
Steps

Step 1. Open the Google application on your device
The icon is white, with a rainbow colored "G" inside. It is usually found on the Home screen and / or in the application menu.
This method allows you to delete the history of all searches you made on Google while logged in with your account (including searches you made on a computer)

Step 2. Press on the "More" menu ≡
This button is located in the lower right corner of the screen.

Step 3. Select Settings
This option is located almost at the bottom of the menu.

Step 4. Select Accounts and privacy
This entry is located in the section titled "Search".

Step 5. Select My Activities
This option is located at the top of the menu. This will open your search activities in a browser window.

Step 6. Press the ⁝ button
It is located in the upper right corner of the page. A menu will open.
If you use Google Chrome as your browser, be sure to press the three-dot menu in the top right corner of the page (to the left of your profile photo), instead of the menu in the top right corner of the window. Chrome

Step 7. Select Delete Activity By
It is located in the first group of options.

Step 8. Select From Start from the "Delete by Date" menu
This will ensure that you clear your entire Google search history, not just the last day's.
If you don't want to delete your entire search history, choose another time range from the menu, or select Custom interval and choose the relevant dates from the "After the day" and "Before the day" menus.

Step 9. Select Search from the "All Products" menu
By default, activity history associated with all Google products (including your search history, YouTube searches, and places you've searched on Google Maps) is selected for deletion. If you want to delete searches only, select Research from this menu.

Step 10. Select Delete
This option is located at the bottom of the page. A confirmation message will appear.

Step 11. Select Delete
This will clear the search history.