how to add a box with text in html code example

Example 1: how do i make a boxin html

<div style="width:500px;height:100px;border:1px solid #000;">This is a rectangle!</div>

Example 2: 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 3: how to style rule to apply the Border Box model css

header, ul, nav, li, a /* other elements */{

 display: block;
   -webkit-box-sizing: border-box;
   -moz-box-sizing: border-box;
   box-sizing: border-box;

Example 4: how to add text box html

<label for="textarea">WRITE COMMENTS HERE : </label><br><br>
     <textarea id="textarea" cols="30" rows="10" placeholder="write here..."></textarea>