drowsy sparrow
Your showcase is what players see when they view your profile. You can show off that Lightbearer with that new skin, that weapon you're quite fond of, your Ghost, your Sparrow and a number of other options. It's easy to do but can be a little hard to find.
Bring up your Ghost and tap your name at the top left of the screen. On your profile screen, on the far right there will be 3 icons for viewing who visited your profile, Settings and sharing your profile. Select settings and the next screen will be where you can edit your showcase. I've made a clip for a visual example. Hope it helps 