Store Logo

In the Admin panel -> go to Storefront -> Logo -> Select "Upload a custom image to use as your logo"

Also, here is an article of BigCommerce for your reference: https://support.bigcommerce.com/articles/Public/Uploading-a-Custom-Logo/

If you want to use text to make your logo:

In the Admin panel -> go to Storefront -> Logo -> Select "Enter text to display as your logo"

If you want to change the settings of the logo:

Go to Storefront -> My Themes -> Customize. (If your store is a new store, you may need to go to Channel Manager -> Themes -> Edit Theme)

In the Theme Editor -> go to Header / Logo

If you want to use logo title here, please do not enter text logo title in Editor.