In sign up form proceed to change the transactional sender's email. (Confirm subscription email)

In sign up form proceed to change the transactional sender's email. (Confirm subscription email)

Hello,

I have created a sign up form. Everything is on place

BUT when somebody subscribe to the list and receives the confirmation email (transactional email), the sender of this email is wrong. I would like is the related to my company domain hello@<my-company.com>. Because this, email is marked as suspicious and forwarded to spam folder.

I have checked the guidelines but can't find how I should proceed to change the sender's email in the to confirm the subscription email 

Settings -> "Manage senders" is not the answer. It works for marketing email campaigns but not for transactional emails like the "confirm subscription"

Thanks in advance