The error you see there is caused by you editing the index.php that is sitting in the same directory as your wp-config.php
That File does not get edited.
You need to stop trying to do things when you dont know what you are doing, and do some reading -- thats what the link at the top of the page that says Docs is for.
Thats called Documentation.
To fix the immediate error you see you need there, to delete the index.php that you have edited, and upload a fresh copy of the one out of the wordpress zip.
There will be atleast 3 of them inside the zip -- you want the one that is inside the same folder as the wp-config.php-sample.
And please, if you are unwilling to familiarize yourself with the basic workings of WP -- hire someone that is, its much simpler in the long run.