Transactional emails and marketing emails
Which emails can't be turned off and which can.
Transactional emails are the result of an action: registration received, order confirmation, bank transfer details, appointment confirmation, password reset. They are sent even to people who have unsubscribed and can't be turned off. Appointment and webinar reminders also don't stop when someone unsubscribes; however, your customer can turn them off in the notification preferences in their portal.
Marketing emails are series and campaigns. They go only to people who have given commercial message consent, and each one has an unsubscribe link.
Don't mix the twoIf you put important information, such as the portal link, only in a marketing email, a person who unsubscribes loses that information. Keep important information in the transactional email.