[php] PHP - how to create a newline character?

Actually \r\n is for the html side of the output. With those chars you can just create a newline in the html code to make it more readable:

echo "<html>First line \r\n Second line</html>";

will output:

<html>First line
Second line</html>

that viewing the page will be:

First line Second line

If you really meant this you have just to fix the single quote with the "" quote:

echo "\r\n";

Otherwise if you mean to split the text, in our sample 'First line' and 'Second line' you have to use the html code: <br />:

First line<br />Second line

that will output:

First line
Second line

Also it would be more readable if you replace the entire script with:

echo "$clientid $lastname \r\n";