DKIM question

we are in hybrid mode with MS 365.  setting up DKIM and DMARC this week.

I was under the impression that MS 365 did have DKIM for our onmicrosoft.com account, but not for our regular domain account, say ourdomain.com and that I needed to add that on our DNS service provider.

but - when I went to email authentication settings I do see ourdomain.com as accepted domain with domain type of Internal Relay.

so my question is, can I just enable this and then NOT have to create DKIM on our DNS service?

I would only need to create DMARC on our DNS provider site?