Slack pioneered emojis in the work chat, but it slacked off when it came to adding the latest emojis. If you can’t find an emoji that you like in Slack, or if you want to make things more fun, try adding custom emojis. Slackmojis is a great resource for downloading still and GIF emojis.
Workspace owners and admins can add emojis to Slack (but guests can’t). To get started, click the “Emoji” icon next to the text box, and select the “Add Emoji” button.
Now, you can either go to the “Emoji Packs” screen to add an emoji pack from Slack’s directory (there are three available packs at the time of writing). To upload a custom emoji, switch to the “Custom Emoji” tab. Here, click the “Upload Image” button to upload a custom emoji. This can be a PNG file or even a GIF file. Give it a name (it will also be the command that you use to enter the emoji), and click the “Save” button. Repeat the process for all the emojis that you want to add.
To send the new emoji, just go to the text box, start with the colon (:) symbol, type the emoji name, select the emoji, and hit Enter.