To create and configure the Emoji field custom field, you must be logged in as a user with Jira Administrator permissions.
Go to Apps → Manage your apps → Custom Field Suite
Click on Create custom field button on the right side of the screen.
Select Emoji field and click Next.
Name and add a description to your field then click Next.
Choose between creating a custom list or let users choose their own emoji
Associate the field to the appropriate screens and click Create. You must associate a field to a screen before it will be displayed.