I want to contact external users using an email address different from the default email address (e.g. @dipartimento.unitn.it) How can I do this?

If you want to change your outbox email address please read here:
https://support.Google.com/mail/answer/22370?hl=it (https://support.Google.com/mail/answer/22370?hl=it) .
You will set your alias as senders and you can choose every time which one you wish to use.

Source URL: https://icts.unitn.it/faq-item/emaildomanda6