This is usually a permalink issue.
Go to your WordPress dashboard then look for Settings>Permalinks.
There will be radial selectable options. You can select any that have no mention of index.php.
Alternative select Custom Structure then in the field to the right insert /%monthnum%/%day%/%year%/%postname%/ then save with the button at the bottom of the page.
I know something like this was in the comments but I wanted to make it clear as possible for beginners.