I rolled a new druid for BofA content after not playing for a while. I’ve got the old cat form. I never got around to getting the druid class mount back in the Legion days, so I’m working on that. Problem is, I cannot get the artifact appearances to work whatsoever. I’ve read almost a dozen posts about this on the forums or on reddit with various solutions. I’ve tried equipping the artifact itself and using the little tree in the Dreamgrove, doesn’t work. I’ve tried equipping a different weapon, and transmogging the appearance onto it (with the little Legion drop-down menu), doesn’t work. I’ve tried resetting the UI, doesn’t work. I didn’t know glyphs were a thing, but I don’t have any applied anyways, so it’s not that. I’m at a loss and have no clue what to do, so alas here I am. I sincerely hope someone has another potential solution 
If it is the shift forms that you are trying to change – that is done through the Barber Shop now.
Druid Artifact Forms Not Tied to Weapon Transmog
In BFA, you can choose an Artifact Tint for Bear or Cat form if you have that specific Druid artifact used as transmog. This really limited transmog options as you were locked into a weapon and had to choose between a unique Bear or Cat appearance–both couldn’t be active at the same time.
By moving Druid form customization to the barbershop, you do not need to select an Artifact Weapon as transmog in order to unlock Bear and Cat form customization!
Unlocks for the Artifact customizations are account-wide, so once you unlock an appearance, all Druids in your account can use them.
The point above include the Mage Tower appearances.
You can use both Guardian and Feral Artifact appearances as customization for any spec
Wow, I never would have thought of that! Thank you!!
You’re welcome.