Hi, It's the same concept when you want to SEO your blog. Kindly keep in mind that Google needs at least 400 words to rank your page. In this case your Shopify eCommerce store, you will need to ensure your home page has 400 words in total including the total count's word from the menu, product title, collection name, and text block. You can use a block of rich text feature on your theme to put some words about your store in order to achieve 400 words on your home page.
The same rule of thumb applies to your collection page and product page. The exception comes applied for collection page in which you can put collection page description like about 150-200 words only if you make it 400 words it looks bad for your collection page UX. The core principle still the same target your primary keyword on your product title, collection page title and home page title. Creating a blog for your Shopify store can help to increase traffic by targeting different SEO keyword and also interlinking to your products. The last thing, you can install the SEO Shopify apps to help you do the job.