How to Change Products Per Row in Shopify Refresh Theme

Refresh lets you set the grid density separately for desktop and mobile, so a layout that looks right on a laptop doesn't end up cramped on a phone.

Steps

In your Shopify admin, go to Online Store > Themes and click Customize on Refresh.
Switch to a Collection template using the page picker.
Select the Product grid section.
Adjust Products per row on desktop and Products per row on mobile independently.
Click Save.

Two columns on mobile is the common default — three tends to make product images and titles too small to read comfortably on smaller phones.