What apps do you use to put emojis on videos?

I mostly edit professional videos, and in that format, emojis are tacky and aren't a good idea.  It looks like the plugin that Christopher mentioned is your best bet, but if you're doing anything beyond SnapChat or fun, personal videos, I'd leave emojis out.

If you are referring to adding an image of an emoji over the video then a Sony Vegas Pro or Windows Movie Maker or really any other video editing software, although Sony Vegas is the best. If you are meaning in another way then consider rewording your question.

If you are using Final Cut Pro X there is a paid plugin called Emoji Pop that does this really well!

why do i get the feeling you are looking for snapchat.

Snapchat seems to work the best for me. This is mostly because you can pin emojis on things by holding it down.