How to make a HTML Page in A4 paper size page(s)?

Question

Is it possible to make a HTML page behave, for example, like a A4-sized page in MS Word?

Essentially, I want to be able to show the HTML page in the browser, and out

Answer 1

A4 size is 210x297mm

So you can set the HTML page to fit those sizes with CSS:

html,body{
    height:297mm;
    width:210mm;
}