Tap the icon of your avatar located in the top-left corner of the screen in the City or Expedition.

In the window that appears, tap the pencil icon or the area with your current name and avatar.

Tap on your avatar.

In the window that opens, select your desired avatar or frame from the relevant tab.

Close the window by tapping the cross in the top-right corner.

Tap the Save button to confirm and save the changes.