There are a few ways to inform Google that your content is original:
Use Google Search Console: Google Search Console is a free tool that allows you to submit your website and its pages to Google for indexing. You can use the tool to submit your sitemap and individual pages, which will inform Google that your content is original and should be indexed.
Use rel="canonical" tag: The rel="canonical" tag is used to inform search engines of the original source of a piece of content. By adding the tag to your pages, you can indicate to Google that your content is original and should be indexed.
Use noindex meta tag: The noindex meta tag is used to tell search engines not to index a specific page on your website. By using this tag, you can indicate to Google that the content on your website is original and should not be indexed by other websites.
Use Google Authorship: Google Authorship is a way to link your content to your Google+ profile, which can help establish your authorship and originality of your content.
Use Copyscape: Copyscape is an online plagiarism checker that can help you detect if your content is being used on other websites without your permission. If you find that your content has been copied, you can take action to have the copied content removed and inform Google of the original source of your content.
It's important to note that these steps can help establish the originality of your content, but it's not a guarantee that Google will rank it higher in their search results, since there are multiple factors that Google considers when determining the relevance of a web page.