Emojis are wonderful right?
Yes they are...
Words are good , but you can tell about your need or feeling through emojis.
So you are able to use the emojis in Dynamics 365 FO as well.
You can find the blog post of Inna Carp;
She beautfully explained where can these emojis can be used.
I also tried with my Mac.
You can right click on a field to add the emojis. You can select from the list of emojis