How can i install google tag manager and google analytics on my website through Cpanel?
You need to edit your website’s code to include the code of the Google Tag Manager and the gtag.js of Google Analytics before the head tag end. You can’t do it automatically through cPanel.
The exact instructions on how to setup Google Analytics or Tag Manager depend on the website software you use. If write your own HTML or PHP code, you can implement it yourself. If you use a CMS or website builder, maybe the website software has an option to set up Analytics, add custom footer code or install a plugin which allows you to do either of those.