Can my department send email?
Yes, through your Klaviyo account once it is connected in Channels. It writes the campaigns and sends the ones you pick to the list you chose: every email waits for your yes, whichever way your department runs. Without Klaviyo, the emails it writes wait as drafts.
Will it email people it found online?
No. Finding an address is not permission to email it.
Where are my subscriber and unsubscribe records?
In your Klaviyo account. Nouna sends only to the Klaviyo list you picked, and Klaviyo keeps who unsubscribed, so a person who opts out stays out of every campaign.