A golden highlight for your avatar frame is a nice way to stand out from the rest of the players. It is unlocked at the Sapphire tier of the Loyalty Program. You can read more about our loyalty program and its tiers here.
A shimmering highlight will appear around your avatar frame once you've activated this feature:


In order to enable the highlight, you need to open your profile by tapping on your avatar and tap the "gear" icon here:


Then tick the highlighted box:



If you still have questions regarding the golden frame highlight, you can always contact our support.