This is how the navbar or Navigation bar looks like

The navbar comes as standard for all blogs created by blogger. Whatever the reason is, if you want to hide or remove it from your blog, follow these steps.

Step 1: Login to blogger as usual. Go to “Layout” and click on “Edit HTML”

Step 2: Add the block of code inside and save the templates.

   #navbar-iframe {

I'm using standard theme - Minimal, if you're using other theme the codes might look a bit different.   Here is a picture showing before and after putting in the codes.

Original codes before adding in the codes.

After copying the block of codes.
Click the "Save Templates" button at the bottom of your screen and you're done.