A noindex tag is a tag you can apply to certain pages on your website. Applying the noindex tag essentially serves as a indicator to search engines, saying that you do not want them to show the specific page in their search results.
This can be a very useful function when used right, but also be very bad for your SEO if used on the wrong page. Because of this, using Morningscore's noindex tag tracker is a great way to make sure you haven't accidentally indexed the wrong pages.