How to remove public in base url?

I installed CodeIgniter 4.1.3 in my subdomain (new.nvslk.com).
I changed the app.php file base URL into my subdomain and move the public folder .access file and index.php file into the root directory. 
however, when I echo the base URL it shows like this "https://new.nvslk.com/public".
I want to remove "public" from the URL. how do I do this?

Thanks 
Anuradha