1 - Install the add-on
In Google Sheets, select Add-ons > Get add-ons.
* Alternative: Click here to install via the Chrome web store.
Then proceed to step 3.
2 - Search for the Geocode add-on
Type geocode in the search bar then click the Free button of the add-on GeoCode by Awesome Table.
3 - Choose a Google Account
Choose a Google account to be used in Awesome Table then click Allow.
4 - Installation Successful
The GeoCode add-on is now successfully installed in Google Sheets. You should be able to see the menu Geocode by Awesome Table and Start Geocoding in the sub-menu.