Setting the referral URL variable
The referral URL variable is the parameter that gets added to URLs on your site to identify them as referral URLs of a specific affiliate.
You can set the referral variable to anything you wish, though AffiliateWP will default to using ref.
Note: When setting your referral variable, make sure you do not use a reserved keyword or term in WordPress as it may conflict with core functionality. Example: "p" which is reserved for pages and posts. View this link for the complete list: https://codex.wordpress.org/Reserved_Terms.
A URL that contains a referral var will look typically look like this: http://yoursite.com/?ref=422
422 is the ID of the affiliate the URL belongs to. In addition, your affiliates can use any of the following affiliate URLs.
The referral variable can be set in Affiliates → Settings→ General:
Note: If you change your referral variable, don’t forget to let your affiliates know.