Short answer
HubSpot's KB: connect an individual work email (needs a Core, Sales or Service seat) to send from records. You can only email contacts you have access to. The From field lists your other connected and team addresses.
1. In HubSpot
The relevant screen in my demo portal.
2. Worth knowing
Add a subscription from the email only when the contact hasn't opted out of all email.
3. Related
Aliases and signatures and open notifications.