html put text in a box 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 add text box html

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