Shopify lets you copy and paste a part of your blog articles to an ‘excerpt’. Shopify SEO excerpt
This does two things – if you are using the ‘show blog on front page’ option or pushing your blog to Facebook, it means you choose the best piece text which goes to the front page. It also means that users only download the excerpt initially (giving them faster browsing) and then they click through to see the remaining text if they want to, which gives your site more ‘clicks’ (which improves your Google ranking). It is not difficult to use – just create your blog post, then copy the piece you want, click add excerpt and paste it in there. Remember to save your blog afterwards.