The traditional ones, made out of paper, are ideal, and I’ve been noticing most every kitchen store carries them. Usually imported from Italy and surprisingly affordable. Leaving the paper on also helps keeping the panettone moist as you should take weeks to enjoy it, peel off the paper as needed.
If you need to buy a metal pan, using a coffee can lined with parchment is the most common make do, works great. I also like to use my 5 qt lodge dutch oven, non-preheated, and lined with parchment. Spray the pan with oil so the parchment sticks.
In general, you should not use a non-stick pan, because you want maximum rise. Panettone rises more than double or ideally triple, and this can only be done by clinging on a very-stick surface. It is tempting to use a non-stick pan, like Kaiser’s mold, you have nice smooth edges when unmolding, but would you use a non-stick pan for a Angel food cake or a Biscuit?