Please how do I add Ruby to html for more functionalities

Answer 1

Browsers only understand Javascript, you cannot run Ruby code in HTML.
There are some ruby-to-js transpilers, eg. Opal, which can turn your ruby code into javascript, which then you can run in the browser.

https://www.quora.com/Why-cant-Ruby-be-used-as-JavaScript-in-browsers

Answer 2

Elimihele Gods favour

Learn about Ruby On Rails which is a Web Application Framework. You can add Ruby code with html code.

https://guides.rubyonrails.org/getting_started.html