The Blogger’s Navigation bar, which we are talking about here looks like this:

It helps you to flag a blog, or jump to next one, but it doesn’t always look pretty with every theme. So if you intend to remove it, follow these steps:

1. Open your Blogger dashboard.

2. Go to your blog’s Layout settings > Edit HTML

3. Look for:

/* Variable definitions
====================

4. And above that add:

#navbar-iframe { display: none !important; }

5. Save your settings and open your blog now. The navigation bar will be gone.

Hope that would help