If you want to remove powered by Blogger copyright widget permanently then follow the steps below:
1. Go To Blogger Dashboard >> Template >> Edit HTML >> Tick Expand Widget Templates
2. Search For Title Text Attribution1 (Use CTR+F)
3. Just Replace locked = 'true' To locked = 'false'
4. Save Your Blogger Template
5. Go to Blogger Dashboard >> Layout >> Click Edit On The Attribution Widget
6. Click Delete Button On The Configure Attribution
9. Its All Done, The Attribution Widget Deleted Permanently.
Enjoy:-!!!