debranding header logo

I would like to ask how to debrand or rebrand the akaunting logo in the left corner. I am able to change the logo itself, but not the text akaunting, next to it. 

in which files can I change this easily?

You can check the views/partials/admin/menu.blade.php file.

This would be a nice addition in the settings pane. Also it would be nice to update the login background picture as well.