In most cases, with marketing emails, senders must get permission from their contacts before sending any marketing campaigns to them. Around the world, many countries and regions require this by law.
When you turn on double opt-in for your Salesforce Commerce Cloud store subscribers, we send your subscribers an email to confirm their willingness to join your marketing lists. You can then be confident you're sending campaigns to valid, monitored, consenting email addresses.
To learn more in Email opt-in types.
Turn on double opt-in
In Dotdigital, go to Connect and select the Salesforce Commerce Cloud tile under Installed integrations and extensions
Under the heading Contacts, for Enforce double opt-in for subscribers, select YES.
Select SAVE.