If you’re using Facebook Messenger on your Android for texting, then you might also want to know how to add emoticons as well as stickers to your text. The implementation of chat emoticons on messages lets you express your emotions without any language barrier. To enable emoticons, while texting, tap in the tiny invisible area to the left of the “+” button on the bottom left.
To get more emoticons, just tap on three little dots. It’ll bring several types of emoticons to you.
To get stickers (This only works in a popped out Chat Head), enable Chat Heads from Notification Setting menu (this feature may not available on your phone) Press the tiny invisible area to the left of the “+” button on the bottom left. That’s all! (Via)