When you enroll to become an affiliate you are assigned an auto-generated "slug" which refers to the identifier in your affiliate url.
For example if your slug is: RNdm12 Your referral URL is: https://discoverhealing.com/ref/RNdm12/
Not fun. You have the option to choose something better ;)
To change your slug to something like your name or business name you will want to go into your Affiliate Area > Settings
Now you can add a custom slug. Please use only alphanumeric, no special characters which may interfere with tracking your referrals.