To invite colleagues to also be an Admin for your organisation. First go to your Admin Dashboard
Click on the "Roles" tile
Then click on the Copy button to copy the activation link invite
Share this link with your colleague. By following the link they can create an account (or sign in) and become a member of your organisation.
To allow them to manage your organisation profile, content and opportunities you next need to promote them to an Admin.
From the Roles screen again - use the status filter to show ordinary members
Then using the 3 dots menu on the right of the row - select to "Make Admin"
You should see a notification the promotion to admin has been successful. Now your colleague will be able to manage your organisation and experiences.