Marketo is capable of sending DMARC compliant email because they support custom SPF and DKIM configurations that achieve alignment, though we recommend relying solely on DKIM to pass DMARC. This source is most commonly known to send Transactional and Marketing automation campaigns and is often used by Marketing and Software Development teams.
The link just below is a resource on how to configure DKIM. You will complete this configuration by (1) following the sources instructions and (2) adding the required entries into your DNS. https://experienceleague.adobe.com/docs/marketo/using/product-docs/email-marketing/deliverability/set-up-a-custom-dkim-signature.html
Marketo's documentation linked below describes how to set up SPF, but Marketo always uses their own domain for SPF unless you explicitly contact support to reconfigure for you. Because of the lack of clarity in their documentation, we recommend configuring DKIM to pass DMARC. https://experienceleague.adobe.com/docs/marketo/using/product-docs/email-marketing/deliverability/set-up-spf-and-dkim-for-your-email-deliverability.html?lang=en