//www.planetminecraft.com/css/fonts.css?v=iAIAFChsfiOXhFo1Q2xw8K3yBUtVao3WmHpU39GNnyc7p4lg,//www.planetminecraft.com/css/style.css?v=Mzlb4K9v3hv5X5CZxGrCkpE3BzZgZmfSANuAViyCIRamr65l,//www.planetminecraft.com/css/editor.css?v=lS1BPzSLq0xR-mdvyBFeB1l5SWusoS2vYRcrVP-3kVh5r65l
MEMBER
[source]
v Profile ➡️ Profile Banner ➡️ Edit
^^You can then choose a different banner if you'd like. Keep in mind: The dimensions of a profile banner matter, and if it's custom, some things could be hidden/cut off. (A perfect example of this is my profile banner, haha.)
The suggested dimensions are: 1070 x 175h (width/height), but you can use one that's any size, iirc.