Change Work Flow Sender

From 'Send An Email (V2)' Flow there is an Advanced option, you can set the sender by populatin the "From" Field. Please take note that before adding the sender you need to add the connection of that email in your flow to be able to use as a sender. You can do this by navigating on the leftside of the Power Automate Dashboard,
1. click Data > Connections > Click New Connections.
2 Populate the credentials that will be used as a sender.