Fine tune your WordPress for SEO: rewrite title, add meta tags, canonical links and more. Out-of-the-box settings are a good starting point for blogs.
Stallion WordPress SEO Plugin enhances WordPress SEO plugins like Yoast SEO and All In One SEO that damage a sites SEO by using noindex or nofollow.
Seo for wordpress plugin will automatically use your post title , content as seo title and seo meta description on new and old posts/pages.
This is a plugin to resolve your duplicate content issue by adding a canonical link to your HTML head section.