Hi @YZF,

Thanks for reaching out to the community!

Although best practice, especially for campaign sending, is to email your subscribed contacts, as long as a profile in your account is active, these users are eligible to receive email communication from you. Active users are either contacts that have opted into email marketing, have simply placed an order on your website AND have not unsubscribed, or have come through another 3rd party integration AND have not unsubscribed. Here is our help center article around Understanding Who Is In Your Account.

Based on the above, you can technically trigger flows for any active profiles in your account. You do have the ability to apply logic to your flows (flow filters, trigger filters, trigger splits, conditional splits) to control who qualifies to receive flow emails. Here is our help center article on understanding Flow Triggers and Filters.

Have a nice weekend!

Julie