Favicon
A favicon is a small image displayed next to the page title in the browser tab. See Shopify Favicon guide here for more details about uploading a favicon to your store.
From your Shopify admin, go to Online Store -> Themes.
Find the theme that you want to edit, and then click Customize.
Click Theme Settings -> Favicon.
Setting
Description
Favicon image
The favicon for your store. The ideal size for a favicon is either 32x32 pixels. If your favicon file is too large, then it will be reduced to 32x32 pixels when you upload it to Shopify.