Brands normally use email marketing management services to utilize email marketing. This is normally called an email marketing software. It sends and manages email marketing campaigns. It has the necessary tools and bandwidth needed for email blasts. Remember, personal email addresses are called as such because that is their purpose : for personal use.
You also need an email list to successfully launch an email marketing campaign. This list includes email addresses who gave consent to receive email marketing campaigns (opt in, as normally called in email language).Make sure you note this part to avoid any violation in data privacy laws.