The principle of connecting the camera through the application to Wi-Fi?

Question

Do it yourself

To connect IP video surveillance that transmits an image using Wi-Fi, for example, to a phone, in the vast majority of cases, when you turn it on for the first time, the camera is connected via USB to a computer, where you enter the Wi-Fi password. Recently I came across a camera (alas, I can’t remember the name), where the camera does not need to be connected to a computer, and you can connect to Wi-Fi through an application on your phone.
Attention to the question, do you have any ideas how to implement such a connection to Wi-Fi through the application as in the second case?

Answer 1

Connect any IP camera to a cheap Wifi router and do whatever you want with it

Answer 2

Instead of a router, you can use a mini-pc, such as raspberry.

Answer 3

Look at this product. It does not require a USB connection to a computer. There are many different cameras and the prices for them are quite adequate. Their quality is good. I have not used it myself, but I have personally communicated with many people who are satisfied.
This one is very easy to install and configure.
But to use their products, you need to install special software on your computer or purchase their NVR.
Maybe you have seen this ? It does not require a connection to a computer, everything is configured through the application on the phone.
You can watch something with a higher picture quality, but this thing seems to require access to the Internet.