How to receive my e-mails on several e-mail addresses?

Technically speaking, it is not possible.

If you want 2 people or more to receive the information, you should create an alias (ssl@domain.com for example) that is redirected to the concerned persons. Just enter this address in the technical contact information of the order form.

Si you manage several certificates, you can open an account and use the 'Generic e-mail address' option in the overall parameters of the account. This way you'll obtain a copy of every email sent to the technical contact. Then you can keep using a nominative email address for your technical contact and centralize a copy of every email.