I wish to create a form which my employees can submit and then my HR dpt can open it and approve it.

If I understood your question correctly you are referring to an approval workflow. If this is the case, you can check the steps provided by my colleague here: http://www.jotform.com/answers/401633#401648 to see how can this be done.

You can also search for some other methods into our support forum: http://www.jotform.com/answers/search.php?search=approval+workflow.

Hope this will help. Let us know if you need further assistance.