The page you are looking at is being generated dynamically by CodeIgniter.
If you would like to edit this page you'll find it located at:
application/modules/welcome/views/welcome_message.php
The corresponding controller for this page is found at:
application/modules/welcome/controllers/Welcome.php
The base url is:
https://sdm.uniska.my.id/
If you are exploring CodeIgniter for the very first time, you should start by reading the User Guide.