Hi @freitasm,
This depends a bit on whether you want a contact to confirm their email address and how important data quality is. There are a few options:
Contact submits form → Redirect to thank you page with direct link to content piece
This is obviously the best user experience. You sidestep HubSpot limitations about the delivery of the email which requires an opt-in. However, if you have the double opt-in enabled and want contacts to confirm their email address, they barely have any incentive to do so. You’re left with fewer confirmed emails than if the content was delivered via email, after the confirmation. Also, you’ll get more made up email adresses (invalid ones) if you do not point on the submission page that the content will be delivered via email.
Contact submits form with required marketing consent → Redirect to thank you page that mentions content will be delivered via email → Content is sent via email
This one only works if your legal team is okay with you making marketing consent mandatory. Typically, this is not compliant with privacy legislation. In this case however, you would have the opt-in necessary for delivering the email. This option will result in higher quality data (fewer invalid emails) and a higher confirmation rate (double opt-in).
Content submits form without required marketing consent → Redirect to thank you page that mentions content will be delivered via email → Content is sent via email
This, I think, is the right way to go, but it requires either a workaround or the transactional email add-on. With the add-on, emails can be sent regardless of subscription status and follow-up emails are typically transactional, since they’re really just a delivery of something that was requested a moment ago.
Without this add-on, a workaround could be subscription type just used for this purpose, which you could call “Confirmation emails”. This is a subscription type that you would opt every single contact into and only use for transactional emails. In the workflow that delivers a follow-up email, the first step would always be to opt a contact into this subscription type, so that the following email has the required opt-in. The email would of course be sent using that subscription type.
If a contact unsubscribes from all email, the content would not be delivered – that would only be possible with the aforementioned transactional email add-on.
Like the previous option, this option will result in higher quality data (fewer invalid emails) and a higher confirmation rate (double opt-in).
(My reply does not constitute legal advice.)
Hope this helps!