You'll find Developer Mode in User Settings > Advanced.

In the right-click menu for any of the fields you've selected, you'll see the "Copy ID" option. Click it!

Once you've clicked "Copy ID", you'll have the message, user, or server ID copied to your clipboard. You're all set!

In a server or group, right-click on your avatar from the list with all the users, then simply press Copy ID like in the Server example!

You can connect it quickly in your SkyPrivate account at Settings > Services.