SendX
Email software to send campaigns, build lists, and automate marketing
SPF stands for Sender Policy Framework.
An SPF record is basically a TXT record with your DNS provider which lists the mail servers or IP addresses that are permitted to send emails on behalf of your domain. SPF validates who is relaying the email.
You can use them to prevent spammers from using your domain for sending unauthorised emails also called email spoofing.
You can check your SPF records from this link.