Convert and protect your PHP scripts to unreadable, but still executable. This is a list of tools you can use to protect your PHP code. 

There’re free and paid tools for encode your php script. Personally I like Byterun Online Free PHP Encoder for a small job, it’s an online tool and cost nothing but if you’re in a big project you may looking for other tools.

What will happenned to PHP scripts after encoded

Before encode

<?php echo "Hello World"; ?>

After encoding

<?php $_F=__FILE__;$_X='Pz48P3BocA0KNWNoMiAiSDVsbDIgVzJybGQiOw0KPz4='; eval(base64_decode('JF9YPWJhc2U2NF9kZWNvZGUoJF9YKTskX1g9c3RydHIoJF9YLC cxMjM0NTZhb3VpZScsJ2FvdWllMTIzNDU2Jyk7JF9SPWVyZWdfcmVwbGFjZSgnX19GS UxFX18nLCInIi4kX0YuIiciLCRfWCk7ZXZhbCgkX1IpOyRfUj0wOyRfWD0wOw=='));?>

As you see PHP code after encoded, you don’t understand it, but this code still executable and the result is the same as result before encode.