Discord allows Nitro subscribers to upload a custom banner image on their profile. Initially, this feature was only available in the Discord desktop application, but it was extended to the mobile app, as well.
Here’s how to upload a custom profile banner in the Discord mobile app.
Step 1: Tap your profile picture in the bottom-right corner of the screen.
Step 2: Tap “User Profile.”
Step 3: Tap your current profile banner.