Definitions, as per Wikipedia:
Sender Policy Framework (SPF) is an email validation system designed to prevent email spam by detecting email spoofing, a common vulnerability, by verifying sender IP addresses.
DomainKeys Identified Mail (DKIM) is a method for associating a domain name with an email message, thereby allowing a person, role, or organization to claim some responsibility for the message.
We do not currently support custom DKIM keys because we sign with our own.
A good article on SPF stuff can be found at https://yoast.com/email-reliability/.
And a good testing tool for SPF stuff can be found at http://www.kitterman.com/spf/validate.html.
If the above is too complex for them, they can use http://www.emailaudit.com.
If you have any questions about modifying your SPF records for BombBomb emails, please contact us as firstname.lastname@example.org to speak with our Deliverability department. These records can be messed up easily, so it is imperative you speak with our Deliverability specialists if you think you need to do this.