For one of my clients, the goal was to migrate old workflows in CE to the new Power Automate flows. One of the requirements was to send dynamics 365 emails in CE which were tracked to activities. This one I struggled a bit to figure out on how to get this to work, so let me share the struggle and hope you don’t lose as much time as I did.
First, it’s important to start from a solution. You need to open or create a new solution, which will become clear in a second. Next, you choose new > Flow and you go ahead creating the flow. Next, choose whatever the trigger is in your specific case.
Now comes the important part. Because we need the CDS (current environment) connector, we need to start from a solution. Since the connector is only available for flows created inside a solution, this is a MUST-DO! Why we need the new CDS connector and not the old one? Because the options to add activityparties are supported in the Current Environment connector!
To create the actual email, select “Create a new record” with the connector specified in previous paragraph:

In our case, we want to send an email when the case is closed to the submitter. Because activity parties are used for the from/to fields of an email message, you need to specify this accordingly. An activityparty consists of an object, so an ID is not enough. We need to add the lookup syntax to be able to determine the object linked. In our case we send from a queue which we determine based on a list records action. Our contact id is directly found based on our trigger, so no need to use expressions there:

To add more information like Subject, Description (which is your actual email body => YES, it supports HTML in the textbox) you need to expand the “Show advanced options”. Finally there, because this will not send the email, it will just create it in a draft state.
To send, we will use another action from the CDS (current environment) connector. It is called perform bound action. This means that we now can execute actions and requests specific to the entity we want. Let’s see how this works:

The action we want to perform is the SendEmail action. If, e.g. we want to close the case and respect all the logic which happens if we do the close action, we can select a bound action on the Case entity and perform the Close action.
I hope I saved you a lot of time figuring out on how to send emails within Dynamics 365 CE. Please share if you found this interesting!