When Googling for the answer to your question I did find this link:
https://www.codeproject.com/Question...e-in-PHP-mysql
But I also did find numerous links with examples on how to do this.
For example
How to File Upload and View with PHP. I am not saying this is a good, or better, article than the rest. Is' just another example of how this can be done.
If you have problems with PHP, the docs have lots of samples, see:
https://www.php.net/manual/en/
I hope this give you a starting point, on researching what you actually need to get started with building this 'online test series'.
