Domain verification (Step 2a) is the recommended method for authenticating your email sending domain.
It offers enhanced security and better email deliverability. By verifying your domain, you establish
trust with email service providers and reduce the chances of your emails being marked as spam.
However, if you don't have immediate access to DNS records, you can use Single Sender Verification
(Step 2b) to start sending emails. Keep in mind that while Single Sender Verification is a quick way
to begin, domain verification is the preferred method for long-term success.