Use Animated Stickers Maker for WhatsApp to create animated stickers from mp4 videos or GIF images.

How to create animated sticker:
1) Select video or image from gallery
2) Trim part of video from which you want to make animated sticker
3) Save sticker to stickerpack
4) Add sticker pack to WhatsApp

NOTE: Animates Stickers added recently in WhatsApp BETA and may not work with some phones.

Animated WAStickerApps