The Howl emote is an Uncommon Fortnite emote. Howl was available via the Item Shop for 200 V-Bucks and you can buy it from Fortnite Item Shop when it will listed.
Fortnite Howl Emote Details
Stand in front of a moon for maximum effect.
Fortnite Howl Emote PNG Images
Here is the PNG images of Howl below!