Email authentication helps with email deliverability. Receiving mail servers scan every email to determine its authenticity before they let emails reach recipient inboxes.
These servers pay attention to a sender’s reputation associated with the sending IP and a sender’s email address domain. Previous problems, such as hard bounces, reports, and poor email body factor into receiving mail servers blocking emails.
Since there is so much fraud, spam, and spoofing that one receives via emails, it is natural that ISPs are adopting strict policies to protect their users. Email senders need an authentic domain for long-term success in their outreach campaigns.
It depends on what email service you use, but the domain authentication process should not be too complicated. You will need to give your ESP (Email Service Provider) access to send emails with your permission through DNS records. Usually, ESPs have step-by-step instructions to help users authenticate email domains.