Display star ratings on the collection/featured collection

Product review apps are not available in the theme package, you need to download them on Shopify App.

Then click Online Store -> Themes -> Customize -> Theme settings -> Product cards -> Product reviews app -> Liquid code - Rating badge (stars)

You need to enter the embed code provided from the app.

Below are some embed codes of popular apps. If not, you need to contact that app's support team, they will assist you quickly.

Loox Product Reviews & Photos Guides online: https://help.loox.io/article/533-integrating-loox-widgets-with-store-2-0-themes

<div class="loox-rating" data-id="{{ product.id }}" data-rating="{{ product.metafields.loox.avg_rating }}" data-raters="{{ product.metafields.loox.num_reviews }}"></div>// Some code

Judge.me Product Reviews Guides online: https://support.judge.me/en/support/solutions/articles/44002237471-adding-the-preview-badge-and-review-widget-online-store-2-0-

<!-- Start of Judge.me code --> 
    <div style='{{ jm_style }}' class='jdgm-widget jdgm-preview-badge'  data-id='{{ product.id }}'>
      {{ product.metafields.judgeme.badge }}
    </div>  
<!-- End of Judge.me code -->