The details shared here apply to the most recent version of our themes. To keep your theme up to date, check out this helpful document.
In all of our themes, you can enable a "hover to zoom" feature for your gallery images on your product page within the theme's settings.
Head into Customize > Select "Product Pages" from the drop-down selector. Under Sections > Product > Product Gallery, enable the "magnify product images on hover" option or "magnify on hover" setting.