Favicons are the small icons displayed on a browser tab to the left of the website's title.
By default, Shopify stores display their iconic green shopping bag.
You can display your own favicon in this spot to match your store brand.
Don't have a favicon? No problem, you can take most any image and generate a favicon file using a free favicon generator. Favicons are usually 16 x 16 px and with a file extension .ico or .png.
How you add a favicon to your store depends on your store theme. In some themes you will add them in the Theme Settings under Header (and the theme may only accept .png files or may only accept .ico files.
If you can't upload the favicon in the theme settings you can do it manually by following these instructions.