Okay, very nice.
How to download chess.com on PC

when u open chess.com, there will be + sign on address bar, there u can download on desktop.
it is not a ''download'', u need wifi, and its browser based

This isn't the case for Chrome or Edge.
There is no plus sign in the address bar
Using Chrome, there is no option to make it behave like an app.
Using Edge, you go to Settings > More Tools > Apps > Use as an App
It creates a desktop shortcut, also taskbar if you like, and opens full page... very nice
Unless you're on a mobile device, there is no "app" to download.
BUT...
I use Chrome, on a PC (a laptop actually) but I also have Microsoft's browser, Edge, installed, and I use it for exactly one thing, to treat chess.com as an app. You go to www.chess.com, then choose "run as an app"... it puts a shortcut on your home page, and on your taskbar as well if you want, then opens without a browser, full screen, no tabs, no search bar, bookmarks, etc.
My program does exactly the same thing. If you're not using a Chromium-based browser, use my program to do it this way, because setting up a site as an app is only possible in Chromium-based browsers.
https://github.com/m3tozz/chess.com