If you want one of your collaborators to be able to manage your organization as you do (add collaborators, send invitations, manage DST...), you can change their role.
To do so, go to the menu at the top right on a desktop or in the bottom right-hand corner on mobile.
Click on My organization.
Click on the three vertical points behind the name of the user you want to change.
You can change his/her status by clicking on Change the role.