HI @jo007, there's no action in Flow to do that. You can send an email when the task is completed but it will go automatically and the flow will go from you as the creator of it unless you use a "Send an email notification (v3)" in which case it will go from Microsoft PowerApps and Flow.
The only possible variation is to use a "Start and wait for approval" action when the task is completed and the user is the approver so gets notified that the task is complete. But any subsequent email will still be sent from you or Microsoft PowerApps and Flow.
Rob
Los Gallardos
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