Do I need to know someone's Apple ID email address to gift them an app? I'd like to send an app from the App Store to somebody as a gift. I have their email address, but I'm not sure if it's the email address associated with their Apple ID. 

Do I need to enter their specific Apple ID email address, or will they be able to download the gift app if the email gets sent to any of their email addresses?
I believe the email sent contains a link with a promo code, it's not bound to the email address.

So you can send it to whatever, they'll still be able to get the app gifted.