We have recently refreshed our branding across our offerings and changed the names of our pricing plans. If you have signed up before Aug 9, 2021, please click Previous plans to view your applicable plans.
We assure you that this change will not impact your product experience, and no action is required on your part.

The default behavior in Freshdesk is that the reply to a ticket would be sent using the support email address from which that ticket was created. 

However, if your requirement is to reply through an email address irrespective of the email address from which the ticket was created, you could install an app called "Customize 'From' Email Address". This can be installed under Admin > Support Operations > Apps > Get More Apps.

Here is a sample screenshot of the app settings.