Mailgun Integration For Transactional Emails

My custom-built site already has an active Mailgun account waiting to be connected. The goal is simple: every order confirmation and account-related notification must leave the server through Mailgun, reach the customer’s inbox reliably, and appear as though it was sent right from my domain... (Budget: $10 - $11 USD, Jobs: API Integration, DNS, Email Marketing, HTML, Linux, PHP, Software Architecture, Web Development)