Beginners questions app/etc

So I forgot my magento2 password and username…It was on a piece of paper and now magic elves have stolen it.

This is only for testing and I can restart an install but I thought to learn more how can I find it

I found a guide to go to:

env.php file which is under the app/etc folder.

But I cant find the location? can anyone just guide me to where the folder is?

env.php is located in <magento_root>/app/etc/