When I first downloaded the app, I was upset because I didn't think it worked.
After leaving a bad review on Instagram, the developer contacted me and told me to allow the app to have full access to my keyboard. Once I did that, it worked great.
After install, go to SETTINGS, GENERAL, KEYBOARD, KEYBOARDS, NIBMOJI then turn on "allow full access". This will fix end copy/paste feature and you will then be able to paste the emoji into text.