How the "Add to Calendar" works
Every event has an "Add to Calendar" functionality present on the public event pages and confirmation email receipts sent to attendees. The "Add to Calendar" is not an invite but merely a convenience for an attendee to add an entry using the event dates to their preferred calendar if they wish.
Besides the event name and its date, the .ics file that is attached to every confirmation and reminder email sent out includes the virtual meeting info and link you configured on the event, plus a short segment of the first paragraph from the event description. An individual can update all of this content when they are creating their calendar entry as they see fit. For example, they may wish to add additional details about the event that is relevant to them.
Important: Anyone who can see the public event details page can use the "Add to Calendar" function. Thus, its content is considered public information. For this reason, be sure not to include sensitive or private information in the event description. Only the iCal .ics file attached to automated emails will include the virtual meeting info and link that you configured on the event.
"Add to Calendar" and Dates Breakdown
Direct, quick links to web calendars, like Google calendar, only support a single date entry into such calendars. Therefore, if the event uses the "Dates Breakdown" feature, then the quick links to web calendars are not available.
In such cases, the iCal .ics file is always the primary way to add the event dates to one's calendar by downloading the attached .ics file and opening it or importing it into the calendar software.
"Add to Calendar" and Virtual Events
There is a dedicated input area named Virtual Meeting Link & Info, as part of Step 1 - Main Details on the event configuration, where you will enter the sensitive virtual meeting info and link that you want to be included on the automated confirmation and reminder emails and in their attached iCal .ics file. This should be used for links to Zoom, Google Meet, Microsoft Teams, or any other web meeting service you may be using.
If you don't want to use the primary way of including such details for virtual events requiring an attendee to have an online or virtual meeting link and sometimes a password, then you can always use the custom email communication message area included on confirmation and reminder emails. Refer to the help doc Custom messages on email receipts and reminders. You don't really need this if you use the primary approach described above.
This flow relies on the attendee getting these private and sensitive details only after registering and immediately as part of their confirmation receipt email. They should rely on that to have the necessary details to join the online event. The attached .ics file will also include the virtual meeting info you configured on the event, or they could copy and paste these details manually from the email content and into their personal calendar as per their preferences.
This will ensure that any private links are only visible to the registered person as part of their registration emails, and not visible anywhere publicly. As explained above, you do not want to include any such sensitive or private information on public event pages as this would allow anyone who sees these pages to join the virtual event without actually registering. For more information, read the Virtual events and classes help doc.
Hiding/removing the "Add to Calendar" function for a specific event
You can choose to completely hide the "Add to Calendar" function from all public pages and automated emails for a specific event. To do so, navigate to Step 1 - Main Details on the event configuration, and you will see a checkbox option below the dates area labeled Hide the "Add to Calendar" function. There is no ability to hide such a function for the entire account as it is a core feature that most events should have, but it is possible for the odd scenario where you need to hide it for a specific event.