As per your question, it can be done by various ways: - For example you can use:
If you want to insert a new line in text area , you can try this:-
Line Feed and
Carriage return
<textarea>Hello Stackoverflow</textarea>
You can also
<pre>---</pre>
Preformatted text.
<pre>
This is Line1
This is Line2
This is Line3
</pre>
Or,you can use
<p>----</p>
Paragraph
<p>This is Line1</p>
<p>This is Line2</p>
<p>This is Line3</p>
Note: if you want to use
\n
you need to install a server like Xampp or Apache to support server side language