How can I resolve duplicate tag pages issue on my website?

[Vicky_123]

While uploading the products on shopify, we have to select the tags and those tags are getting crawled as different URLs, due to which there is a duplication issue on the website in which we have added the content. We have tried blocking those pages through adding wildcards in robots.txt and also not able to add "noindex nofollow" tag or canonical tags in the backend as those pages are not available in the backend of the website.