add text to another box html code example

Example 1: how to make a textbox in html

Simple code:
<input type="text" name="textbox_name" id="textbox_id"
class="textbox_classname">

Apart from this there are many other attributes are there which we can use in textbox
> placeholder
> style
> value 
etc..

Example 2: how to get the input of a textbox in html

//HTML Textbox w/Getting Javascript Input:
<script>
  function getTextBox(){
    var k = document.getElemntById('myTextBox').value
    alert(k)
  }
</script>
<input type="text" id="myTextBox">
<button onclick="getTextBox()">Get Text Input</button>