In order to remove the Search Icon on your Header, follow these steps:
From your WordPress Dashboard, go to the Appearance > Customize > Header > Header Main Area section.
Toggle off the Enable Search Icon option.
Click on Publish.
It is shown in the images below:


From your WordPress Dashboard, go to the Appearance > Customize > Header > Header Main Area section.
Toggle off the Enable Search Icon option.
Click on Publish.
It is shown in the images below:


Updated on: 14 / 10 / 2020