The storefront link for a seller can be displayed next to all their listings if their storefront subscription is current and their storefront is on. If those terms are met their storefront could be set to display within the category browsing results in a column to the right if using the differing browsing views as shown below:

The above is where the link appears by default in the grid browsing view.

This screenshot shows display within the list browsing view.

and the screenshot from within a gallery browsing view.

You can control that on a site wide level within the following admin tool:

LISTING SETUP > FIELDS TO USE

You'll also find the same controls on a category by category basis within the category specific field configuration feature explained in more detail here.

You'll find a Storefront Addon's Fields section within that admin tool if the storefront addon is enabled within the software. Look to first turn that feature on as shown here:

Once the feature is enabled you would set it to display within system page, modules and addons using the tabs shown here:

Within the above we've turned that link to appear in the category browsing feature. You only need to check the boxes for those features you want that to appear in.

You'll see the same controls for module, pic modules and addons like shown below:

You can control what icon (or text) that appears as the storefront link icon within the text admin for the storefront addon here within the admin tool:

ADDONS > STOREFRONT > EDIT TEXT

You can edit any text attached to the storefront addon within the above admin tool. You'll see configurations for each language within your site. But you'll see a configuration like the following specifically for the storefront link icon:

We set an icon to use there but you can use text or replace the icon with one of your own.