Whenever I am sharing a post wordpress phrase is automatically added, can anyone help?

There’s a reason people say that you shouldn’t download free themes from outside of wordpress.org, they might contain hidden surprises

In your case, the theme inserts an advertisement at the beginning of the post content div:

<div style="position:absolute;top:0;left:-9999px;">Want create site? Find <a href="http://dlwordpress.com/">Free WordPress Themes</a> and plugins.</div><div style="clear: both"></div>

Since the style.css indicates this is a themeforest theme, and since the site dlwordpress.com offers it for free, this is a pirated theme and this kind of problem is to be expected

This has nothing to do with Yoast or other plugins, and it’s a hardcoded surprise added to the theme by the pirates.

Instead, consider buying the real version of the theme for $49 USD on Theme Forest instead of using a dodgy copy that might contain other hidden surprises and malware