Yes, no problem. Go to your Subscribers section where you'll find a list with all your email subscribers.

At the top right there is a button labelled "Add subscribers". If you click this button, a modal with an input opens. You can add one or multiple emails at the same time (one per line or separated by comma).

If you hover an email address in the list, a small bin icon will appear next to it. Clicking this will delete the email subscriber permanently from your Authory account.