WhatsApp sticker function has 12 sticker labels that are now downloaded free from the Sticker Store. And now there are third party applications that make WhatsApp stickers.
Currently, there are two third party applications called Sticker Studio and Sticky Notes for WhatsApp, which allows you to create your own labels. Versions may vary, but you can mainly use the images to be imported into the application or capture a photo, and then show the portion of the image that you want to use as a sticker.
You have at least three stickers to publish, and after publication, you can use your WhatsApp stickers in your app. Now these apps are only available on Google Play, so iOS users can not create their own labels but in the near future iPhone users will develop iOS applications, which will allow them to create their own label for WhatsApp.