Where to Find Your API Key
Log in to your Brevo account.
Click your name in the top right and select SMTP & API settings.
Click the API Keys tab.
Click Generate a new API key if you do not have one, or copy an existing key.
Paste it into the Brevo card in the plugin and click Connect.
Finding Your List ID
In Brevo, go to Contacts → Lists.
The list ID number is shown next to each list name in the list view.