I am the admin of a Facebook group and I want to export all the email addresses of all users. How can this be done?
Even if you are admin of a fb group you can't have access to your members email addresses. Why? Because someone may be part of a group you created without being your friend. And because of this limitation, even as an admin you do not have access to their privacy even though they are part of your group. The only option where you can export the addresses of people is by making a backup of all your data on fb and you will be able to see only emails of your friends who have enabled the option of letting you download their emails.
Facebook: export your friends' email addresses, if they let you
How To Export Your Blog Subscriber Email Addresses - Explained in Detail With Screenshots