Use canonical tags
1. Use a tool like Siteliner or run an SEO audit on Ubersuggest or SEMrush to find all the existing pages with duplicate content.
2. Copy or export the URLs of duplicate content to a spreadsheet or text document.
3. Decide which version of the page you want search engines to index.
If you have upper case and lower case URLs, choose the lower case URL. Choose the correct URL version. If you force the use of SSL on your website, use the https and not the http URL. For WWW and no WWW, it doesn’t matter which you choose, but you must pick one.
4. Add rel=canonical tags to the section of your duplicate pages to specify which pages search engines should index.
Replace “https://domain.com/chosen-page” with the version of the page you want search engines to index. If you’re using WordPress, canonical tags can be added using an SEO tool like Yoast. Navigate to the Yoast SEO metabox on duplicate pages, enter the ‘Advanced’ section under the ‘SEO’ tab and type in the full URL for your chosen page, including https and WWW where applicable. If you’re using an ecommerce platform or a website builder, check your documentation for more information on where to add canonical tags. For instance, canonical tags are automatically added when using Shopify. Some website platforms and CMSs have this feature built-in, but it’s best to confirm this with your web developer or platform tech support.
5. Reach out to your web developer to code in canonicals for parameters.
For example, https://example.com/sample-page/ and https://example.com/sample-page/?sessionid.