How do I output multiple user input to the screen with PHP

//HTML CODE BELOW

<form action="bot.php" method="POST">
		
		<input type="text" name="username" required=""/>
		
		<input type="submit" name="submit" value="submit"/>
	</form>


//PHP CODE BELOW
<?php
	
	//request name from form
	 $username= $_REQUEST['username'];
	 
	 //create function
	 function msg(){
		
		$username=$_POST['username'];
		echo "$username";
		echo "\r\n";
	}
	 
	 //ourting input to screen
	 
	 if(isset($_POST['submit'])){
		 
		 msg();
	 }
	 		
?>