How to add image on our head?

LelioMods i suspect that u want a decal on top of a players head, so just make a rig and put a BillboardGui inside the of the head, and put a ImageLabel inside the billboard, u can customize the decal to any image u want. Then, put the billboard inside of ReplicatedStorage, and insert a script into server script server and type this:

game.Players.PlayerAdded:Connect(function(plr)
    plr.CharacterAdded:Connect(function()
        local player = game.Players.LocalPlayer.Character
        local billboard = game.ReplicatedStorage.BillboardGui:Clone()
        billboard.Parent = player.Head
    end)
end)

also, set the "AlwaysOnTop" property in BillboardGui to true, make the billboard size the same as the ImageLabel size too, and make the billboards SizeOffset to "0,1", also u can make change the maxdistance.