You need to be on the Free plan before applying for the Special Code
Please follow the steps:
Go to Settings -> Billing
Click on "I have a special code" link at the bottom of the page
Paste your Special Code in a popup form and click the Validate button
After Code is successfully validated you can Save it to apply.
If the Code isn't validating:
Check if it was copied correctly (spaces, extra symbols, etc)
Make sure it's not expired as each code has limited time for application (contact the Code provider if you aren't sure)
Contact us using email: [email protected]