Assalamualaikum and hi, this tutorial is to remove the attribution. Blogger refrains people from remove "Powered by Blogger" because this widget is locked. You can either unlock the widget or just remove the attribution codes. As I think removing the code would be better and easier, I'll only show you how to remove the code.
Dashboard > Template > Edit HTML
Click "Jump To Widget"
You will be redirected to this code:
<b:section class='foot' id='footer-3' showaddelement='no'>
Delete all of them and save.
<b:widget id='Attribution1' locked='true' title='' type='Attribution'>
Labels: HTML & Design