Update: As of June 2019, Walmart’s affiliate program is now being managed by Impact!
If you signed up for the program before June 2019, then you’re probably participating in the Walmart affiliate program as managed by Rakuten Linkshare. Both programs are still officially supported and we haven’t heard of any plans to deprecate the Rakuten program. If you’re signed up for Walmart (Rakuten), there should be no need to sign up for Walmart (Impact).
You can find instructions on how to add in your Walmart Partner IDs in our Knowledge base: Rakuten or Impact.