Starter and Growth can send email campaigns. Connect SMTP first.
Go to Emails → Campaigns.
Create a campaign, write the message, and choose a supporter list as the audience.
Preview, then send. You will be asked to confirm the list name and size.
Respect consent and unsubscribe rules for your region. Only email people who expect to hear from you.
If you need a drip (wait, then email, then branch), use Automations instead of a one-off campaign.