Shopify does not allow you to edit robots.txt files; which can cause some issues with crawlability. This is one of the main limitations with Shopify if you own a large ecommerce site as Googlebot may be able to crawl irrelevant URLs at scale.
A potential workaround with this is to include a + in collection or blog URLs that you want to block in robots.txt as these are included in the default robots.txt file:
Noindex, nofollow controls
To control which pages appear in Google’s index, Shopify does allow you to apply both noindex and nofollow tags.
Noindex can be added to the theme.liquid file to help control which pages are crawled and indexed at a page, or template level using the following method – https://help.shopify.com/en/manual/promoting-marketing/seo/hide-a-page-from-search-engines
Nofollow can be included using the same method, however, by including “nofollow” instead or, or as well as nofollow (for example noindex, nofollow).
However, there are also apps that can help with a less manual method of implementation. Below are some example of the apps that we use with our clients:
Shopify Sitemap and Noindex Manager App
Shopify does allow you to redirect URLs (Online Store > Navigation > URL Redirect > Create URL Redirect). This is an easy and intuitive system to easily control redirects which is great.
However, there is a limit of 100,000 redirects with Shopify straight out of the box.
100,000 redirects sounds like a lot, however, if you’re running a medium-large ecommerce site that has a large product turnaround these numbers can quickly add up.
If you’re migrating to a new domain, or away from the Shopify CMS this can also pose an issue, since you may not be able to redirect all the pages on your site.
Global redirection (for example non-www to www versions of a site) can be implemented via Online Store > Domains.
Here you can set a primary domain (the version you want to be accessible), in addition to any third party domains you have registered. These third party domains will automatically redirect to your primary domain if accessed.