After finishing Prestashop installation on your domain name, you try accessing it. It by default loads with index.php. Example: http://www.example.com/index.php
If you wish to exclude OR remove this index.php from being displayed, you need to enable Friendly URL. You can use this option only if your server allows URL rewriting.
Login to your Prestashop admin panel & access option Preferences >> SEO & URLs. Under Set up URLs find for Friendly URL. Set it to Yes & click Save.