By default, the .php extension will show in a web browsers address bar. For example, if you've a page named About.php, the address bar will show www.example.com/About.php.

Update the try_files directive in your main location block in your nginx.conf file to have @extensionless-php.

location / {
    try_files $uri $uri/ @extensionless-php;
}

Also add an @extensionless-php location block and restart nginx for this change to take effect.

location @extensionless-php {
    rewrite ^(.*)$ $1.php last;
}

Now, .php will no longer be displayed.