Yes! But by default smallstep licensing (free version) includes a single admin only.
To upgrade, please contact support and let us know which plan you would like to implement.
If you are licensed for more admins but don’t see a way to administer them in the UI, just open a support ticket and we’ll make sure the feature is enabled.
If you require assistance adding or changing users, be sure to include first name, last name, and email address in the ticket description.