Change title in storefront theme

hi I am trying to configure the storefront theme more like a catalogue than a shop
Where can I change the text which appears above the categories:
<section class=”storefront-product-section storefront-product-categories”><h2 class=”section-title”>Comprar por categoria</h2><div class=”woocommerce columns-3″><ul class=”products”>

My main language is spanish so I want to change the part that says “Comprar por categoría”

thank you