If you want to recommend CoinTracking to your friends you can send your so called Affiliate or Referal Link (RefLink) to him. You can find on the Affiliate Programm page in your account here.
Copy this link and send it to your friend e.g. via E-Mail or Messenger.
As preparation you need to add a Bitcoin address and for legal reasons your recipient information. A payment to you is only available via Bitcoin.
Your friend creates an account at CoinTracking using your link. If he is ready to upgrade, it might be necessary to clickon the link again (depending on the Cookie settings within the browser). If the 10% discount banner is shown on the top of the upgrade page, the referral link is active.