Adding html page to Yii2 basic

Yii 2.0 Installation and Setup
1

I have a running website on yii2, but wanted to host pwa app on the same url. I want to run it on example.com/app
I tried putting the html and js files to the web directory, but opening example.com/webapp/index.html gives me 404 error, other files do open, but not main index.html file

2

Because it’s index.php?

3

My webapp is index.html

4

There is only one working file named index.*.
What file *.php or *.html is working you will see in .htaccess / apache settings
Regards