Accessing the Editors Panel
Click your profile picture in the top right corner of 7TV and select Settings from the dropdown menu.
Once in Settings, select the Editors tab from the left-hand sidebar. This will bring up the Editors management page, where you can see everyone currently editing your channel.
Adding an Editor
In the top right of the Editors page, you'll find the Add Editor field. Type in the 7TV username of the person you'd like to invite and confirm your selection.
When adding a new editor, you'll be prompted to configure their permissions. You can read about these here: What are Editors on 7TV?
Once permissions are selected and confirmed, their entry will appear in the list with a Pending status until they accept the invitation.
Removing an Editor
In the Editors tab, find the user you want to remove and click the trash icon on the right side of their row.
The editor will immediately lose all access to your channel upon confirmation.
Editor Status
Accepted: The editor has full access based on the permissions you granted.
Pending: The invite has been sent but not yet accepted.