How to enable users to add the Appointment to their own calendar?

2) Once the user chooses their date and time, how can I enable them to add that information to their own calendar?

Hi roloxls,

Thanks for reaching out to Jotform Support. While the feature you're looking for isn't available at Jotform right now, we've gone ahead and escalated your request to our developers. Exactly when or if it's developed depends on their workload, how viable it is, and how many other users also request it. If there are any updates, we’ll circle back to this thread and let you know. 

In the meantime, you can use send reminder email feature in the Appointment element. Let me show you how:

1. In Form Builder under the orange navigation bar, click on the Appointment element.
2. Choose Gear icon to open Properties. Click on the Advanced Tab,
3. Turn toggle On to Send Reminder Email. Close the panel on the right. That's it.  

Thanks for your patience and understanding, we appreciate it.

Thanks!