I created a text file and saved it as php.ini and the file only has one line in it (allow_url_fopen = On) and there is nothing else at all in the entire file, is this right?
Yes, that's right, a new file containing only this one line.
Do you mean put this (php_value allow_url_fopen on) on line 123 and nothing more? No open and closing tags of any type, just that one line on line 123?
Yes, you understand it correctly, php_value allow_url_fopen on to new last row without tags