"Ask in PowerApps"

@Greg Burton

1. I don't know why you add a tile for sending an email, unless you are just playing around and testing out functionalities.
2. In the Power Automate for the button in Power App, change the trigger from Power App to Power App V2, much better control of parameter passing between Power App and Power Automate

@Greg Burton
If this is a planned production use of Power App, I advise against it.

your fundraiser does not need to copy and paste, since you said outlook, if the fundraiser simply click on the email address, it will open outlook with the email already filled in on an outlook new message window.

I would also recommend you look into the Outlook addin:

If you really want to get the PowerApp to work, like I said, use PowerApp V2, but you have to know how to use it, it doesn't magically work.

From within the Power App you need to call the Flow and provide the parameter needed by the flow to send email to it.

UpdateContext({FlowResponse:'SMSNXT-AddAssignment'.Run(varSelectedGift.REGiftSysID, 'DataTable-Student_A'.Selected.ImpactId, Int('Input-Amount_A'.Text), varDefaultYear, "Confirmed")});