The document says "Please note: an unsubscribe link will not be added to emails sent from Gmail or Outlook, even if you have the HubSpot sales extension installed. " but the links are most definitely being added as I can see the links in the emails in the sent folder of my connected Outlook account.
What exactly happens when a contact clicks on the link in an email? Is a note added to the contact record? Will I be prevented from sending that contact any more emails?
When someone clicks on unsubscribe link, he/she will get an option to select which subscription he wants to be opted in and from which they want to get opted-out.
After doing so, you can compose and send your email from HubSpot.
By default, however, HubSpot would exclude this contact automatically from any communication from your portal (marketing emails or sequences, for example).
Keep in mind, that you need to respect the choice of the recipient and should discuss this matter with a legal professional if you’re in doubt about the legality of some of your emails. (This post does not constitute legal advice.)