How to Get Emoji IDs on Discord (Without or With Developer Mode)
On Both Mobile and PC:
Ensure you are in the server that has the emoji you want to get the ID for.
In the chat box, type \:youremojiname:, replacing youremojiname with the name of the emoji.
Send the message. The ID of the emoji will appear in the chat as \.
Copy the ID number from the message.
Now using the converter, if the emoji is animated, use the GIF format in the dropdown, if not, use WEBP.
Once done, insert your copied emoji id into its respective placebox. Then click Convert!
Once converted, just double click the link that has been created and copy it, once done, you can post it anywhere, and it'll turn into your EMOJI!
Note: This method only works if you are in the server that has the emoji. If you are not in the server, you won't be able to retrieve the emoji ID using this method.
How to Enable Developer Mode on Discord (if you're unsure or if it doesn't work somehow)
On Mobile:
Open the Discord app on your mobile device.
Tap on your profile picture in the bottom right corner to open User Settings.
Scroll down and select Advanced.
Toggle the Developer Mode switch to enable it.
On PC:
Open Discord on your PC and log in.
Click on the gear icon (User Settings) at the bottom left corner next to your username.
Scroll down and select Advanced in the left sidebar.