Dougal Campbell

HeadMeta creates <code><meta></code> “description” or “keywords” tags for individual 
posts or pages. It can also create arbitrary <code><meta></code> or <code><link></code> tags. 
These are easily set on a per-post (or page) basis by simply adding Custom 
Fields.
See the Installation section for more detailed examples.

HeadMeta

Automatically add <link>, <meta> description and <meta> keywords to your HTML on a per-post (or page) basis.

Jayesh Parejiya

Add Meta Tag For WordPress is a Free metadata plugin for the WordPress that can optimize your web site for more efficient indexing of your content by search engines.
<h4>Features</h4>
Metadata Option about the sections above:
<ul>
<li>Enable Meta Tag</li>
<li>Display in Page</li>
<li>Display in Post </li>
<li>(Display in Page or Display in Post) + Display Schema Org</li>
</ul>

Add Meta Tag For WordPress

Add Meta Tag For WordPress very easy setup.
I am really loving it!
Let me know if need help :)

Awesome and great plugin for Add Meta Tag For WordPress

this plugin that you can add metadata your web site for more efficient indexing and easier sharing of your content.

HeadMeta vs Add Meta Tag For WordPress