There are two ways to automatically send email to new users, and you may way to use one or both of them. They can both be enabled in Settings -> Organization -> Edit Organization:
- Send email transaction receipts: check this off to send email receipts of all transactions. This includes creating a new user account with a membership/subscription.
- Send new account email: Sent when an account is created and can be used with or without the transaction receipts. If you do have "send email transactions receipts enabled" this will send a "second" email when the account is created.
Many organizations just use email transaction receipts. Some organizations use both if they have special instructions for users when they first register. We plan to combine these two messages into one in the future, but for now, it will generate two emails. (Many other sites do this as well, but we understand it is not ideal).
You can modify the email templates in Settings -> Users -> Email Templates as described in our Email Templates help article.