Hey @BarryW1812! I talked through the differences between a branded subdomain and root domain in this recent post:

In short, a subdomain like send.company.com will not affect the root domain of company.com, which is why you’re setting up the subdomain in the first place. Separately, though, you definitely should be updated to the new DMARC sender requirements. Check out our handy dandy guide to walk you through this!

Kaila,

Thank you for the reply, but you didn’t answer the one question I specifically asked.

“Can I place my Branded sub domains on CompanyBrandA.com and CompanyBrandB.com despite that they have no email capabilities/configuration at all ?”

Thanks

Barry

Whoops! My bad, @BarryW1812. I was checking on this internally because I don’t want to give you incorrect information. I’ve opened a Support ticket on your behalf to get this prioritized. When we get a proper answer I’ll update this thread for future readers.

You should get an email from Support soon. :)

Kaila,

Thank you

Barry

following to get notified of the follow up as I have a similar question

I have an update from our Deliverability experts! 

So, email sending via Klaviyo does not require an active mailbox to receive email. You can send from any address you choose which matches your branded sending domain. You can set the reply-to address to an email address where you are able to accept mail so that recipients can respond back to your emails, however this is not required.
 
When setting up a branded sending domain on Klaviyo (here's a guide on how to do that) - SPF and DKIM are fully managed for you. You will not need to manually add records beyond those required to connect your domain to Klaviyo. Klaviyo branded sending domains are setup on a subdomain of your choosing.
 
That said, you can only have 1 branded sending domain per Klaviyo account, so you will want to choose a sending domain that aligns with the particular sender email address used for your sending. This means in Barry’s example above, he cannot use sending emails addresses with BOTH companybrandA.com and companybrandB.com. He’d need to pick one or create a separate Klaviyo account to use the other.

I hope that helps! :)

Thank you for getting an answer to the question.

That is exactly the info I needed.

Barry