PHP Date - How to add a string to separate date and time

you need to escape the a and t as both have special meaning when used as formatting options in date()

echo date('M j \a\t h:i a');

See it in action

Try

<?php
    echo date('M j \a\t h:i a');
?>

OR

<?php
    echo date('M j'). "at". date(' h:i a');
?>

You need to escape the t too:

echo date('M j \a\t h:i a');