Duplicate content refers to blocks of similar or exact texts placed across pages or domains, and it may be used to get more traffic or to manipulate the ranking in search engine result pages.
Duplicate content refers to pieces of content across pages and domains that completely match other content on the web or within the same website (or the text is appreciably similar).
Most websites duplicate content on the pages in order to manipulate search engines to rank higher in the result pages (SERP) and get more traffic.
If a website contains multiple pages with largely identical content, there are several ways you can indicate your preferred URL to be indexed by Google - This is called canonicalization.
If Google perceives that a website has duplicate content aiming to manipulate the ranking, the site might get a penalty or be removed entirely from the Google index, in which case it will no longer appear in search results.
There are multiple ways to address duplicate content issues and ensure that visitors see the content you want them to, but here are the most common to approach:
Minimize similar content. If there is similar content on multiple pages, try to extend the content, rephrase it, or merge it into one page.