1. look at the bottom of your blog.
at this article, i use template from ThmeXpose. Another template should be done with the same way.
2. goto blogger dashboard
search for "Template Designed By", comment by add <!-- at the front and add --> at the end. it will look like this <-- / Template Designed By : -->
3. adding style visibility hidden will make it disappear
add style='visibility: hidden' at the <a> element.
4. Save Template, and refresh/reload your blog.
you can watch video tutorial here :