First you have to login your blogger account. Go to dashboard.
Now choose a blog where you want to hide navbar.
Go to Design > Edit Html.
Back up your template (first make sure you have completely back up your template).
Now look for the code in your Blog HTML
Now paste the below code before the above code
Click on preview to make sure Navbar is hidden.
That’s it. Now click on save template (This procedure will hide the navbar from your blog).