If you have problems submitting your payment or if you see error messages, please make sure you have cookies allowed, clear your browsing data/cache, reload and repeat the steps all over again. Using another browser might do the trick as well.    
  

1. Log in and go to "Your Account" page
   
Click on your email address on top right.


2. Select a suitable subscription and billing plan
You will be forwarded to "Billing address" page.





3. Add contact and billing information
Click on "Next" below if done.



4. Enter credit card details
Click on "Submit" to confirm.