for example, i have created a .php file in ANSI encoding (non-UTF8),
then, in the beggining wrote there a code, like <?php echo 'hello';?>,
then saved, then reopened and changed encoding to UTF8 and saved again.
DO you know what happened?
Notepad++ cant see, but in the start of the file, there is added an unknown character in front of <?php. Notepad ++ cant see, but HTML-Kit (another software like Notepad++) can see. THats because, that that extra character in the start of the file causes some errors in PHP programming.
here i have attached a sample file, where Notepad++ cant see that charachter, but if you open this file with HTML-KIT, you will see!