can i give or add username and password to my web app (public url). so that no one can access the web without login credentials
Certainly , you can secure a public URL by configuring it as a protected link. To achieve this, navigate to the Share > Public URL configuration. Within this section, you’ll find a toggle that allows you to convert the public URL link into a protected one. For detailed instructions, please refer to the relevant article at: Public and Embed Sharing options | Build stunning internal tools, blazing fast
I hope this helps you. Thanks.