When a search engine does SEO optimization, such as google, for example, "unique content" is a term that means unique text - and this is structured text content that is completely different from any other prior publication of content on the Internet, which in turn is found and indexed by google.
So we can have 100% unique content by posting a text message that until now has not been published even in some partial form. In general, google favors this site, which is the first to publish any content, and thus begins to rank the site in question better by the set of keywords and phrases contained in the title itself and in the text of the publication. It's good to know that you posted some content first, and google finding that content first with you are two completely different things.
Unique textual content is of utmost importance for both the SEO of your site and its accessibility. This will give you the correct presentation and the ability to index faster than google. If you want quality content for your website, you need marketing management.