Go to this link.
Insert the required data then click on "Register".
Go to your inbox, you'll find an e-mail from iWASEL VPN with an activation link attached.
Click on the activation link then click "Log in" and insert your e-mail and password to view your profile.
You'll find an unpaid invoice.
Click on one of the key buttons on the left to choose a subscription package.
Go down the page, insert your voucher code and click on "Submit".
*Make sure you didn't copy any spaces while you're copying the code.
*Make sure you copied the code starting letters from the left.