Help Scout is capable of sending DMARC compliant email because they support custom SPF and DKIM configurations that achieve DMARC alignment. Help Scout is a Customer Service Platform and is often used by Support.
The link just below is a resource on how to configure this source to send DKIM-aligned email on your behalf. You will complete this configuration by (1) following the source's instructions and (2) adding the required entries into your DNS. https://docs.helpscout.com/article/666-dkim#setup
The link just below is a resource on how to configure this source to send SPF-aligned email on your behalf. You will complete this configuration by (1) following the source's instructions and (2) adding the required entries into your DNS. https://docs.helpscout.com/article/58-spf-records