It is not possible to delete a template. However, you can hide the template by following the next steps.
1. Go to 'Templates' from your home screen.
2. Click on the specific template you want to delete.
3. Click in the upper-right corner on 'Options' and a list of options will appear.
3. Unpublish the template before archiving. Without unpublishing the template it is not possible to archive it.