Yes, an email address is required when creating a recipient.
For most transfer types—EFT, ACH, Fedwire, UK Faster Payments, SEPA, and Wire (SWIFT)—the email is used only to optionally notify the recipient when a transfer is sent. If the recipient does not provide their email, you can enter your own instead and still proceed with the transfer, as long as the account details are correct.
However, for Interac e-Transfers, the email must belong to the recipient, as it is part of the required payment details to complete the transfer.
In short:
Email is required when creating a recipient
Email must be the recipient’s only for Interac e-Transfers
For all other transfers, you may use your own email if needed for notification purposes