How to add custom favicon

With WordPress 4.3 and on, you can add a favicon or site icon from the WordPress admin area. Follow these steps to add a  favicon in your site:

Prepare image: The site icon image should be a square; you can also use a rectangular image. and WordPress will allow you to crop the image once you add it.

Go to Appearance > Customize and click on the Site Identity tab

Click on the select image button. Then, upload the image you want to use as a favicon.