When you order a software license and your order is complete, you receive an order confirmation email and an order fulfillment email. The order fulfilment email contains the registration code to register the software.
Please copy the registration code from the order confirmation email. The registration code looks like the following (do not copy from below, copy from your order confirmation email):
Start the software and select Help->Register under the main menu (PC or Mac version). The registration window has one long text field where the registration code should be pasted automatically if you copied it correctly. If the registration text field is empty, paste the registration code there.
Click the Register button to activate your registration code. If the registration code is correct, you will see the "Registration is confirmed. Thank you!" message.