How to add Mailgun apikey or Office365 box In Heartsender V5?

How to add Mailgun apikey or Office365 box In Heartsender V5? How to add Mailgun apikey or Office365 box In Heartsender V5? Dark and Light Theme Multi Email List For every category QR with multi size Embedded Image Html to image Sending Speed improved with threads zip Attachment Improved and very easy to use GUI…