Foam or no foam?
The foam that forms on top of the matcha tea when you whisk it is something that many strive for as the foam enhances the taste and texture of the tea. The matcha becomes creamier and smoother. It is easier to get a good foam if you use a high quality matcha, a larger amount, the right temperature of the water, the right tools and whisking technique.
And on the other hand, if you want a milder, thinner and less creamy matcha, the foam is not necessary. So whether you prefer foam or not, it's up to you and what you prefer.