How can I edit robots.txt of my Shopify store?

What is a robots.txt file?

Robots.txt is the file to tell search engines which pages should be crawled or not. It's is mainly used for keeping a web page out of Google search results. You can find the file under your store www.your-store.com/robots.txt. 

How can I change it?

In June 2021, Shopify allows editing robots.txt via the robots.txt.liquid file in the theme editor. You can follow this article - Editing robots.txt.liquid. Please note that changing this file may result in a loss of traffic.

Reference:

Hiding a page from search engines: https://help.shopify.com/en/manual/promoting-marketing/seo/hide-a-page-from-search-engines