How to add HTML in TextAreas to WordPress?

Okay, so I run a tutorial/blog/resource site & I noticed that when I put HTML Codes into the Text Areas in WordPress I keep seeing this <p>! It’s messing up the HTML Codes! So I need to know if there is a plugin, or is there something else I can try! I tried these plugins already:Wordpress Code Snippet & SyntaxHighlighter Plus, none of them work! Any tips? Thanks in advance! 🙂
And the <p> appears inside the text area…:/