To be a delivery captain takes years of experience handling a variety of boats over many miles of water. Amateur sailors can transition to professional delivery crew or even a captain over time, but it will take some work. Being a delivery captain is a genuine job, with real required skills and certifications. At a minimum, you would need several offshore passages, and sufficient sea time to qualify for and pass the USCG Masters License or a RYA Yachtmaster Ocean certification. These credentials require verified sea time and experience. There are ways for enthusiastic but inexperienced sailors to get the required experience, as volunteer crew on yacht deliveries, and crew for cruising yachts on ocean passages. Some delivery skippers may take unpaid crew who are looking for sea time, though you'd probably be on your own getting to the boat and back. You would get an excellent experience. Many full-time cruising couples also pick up volunteer crew for large passages, and that's another way to get your sea time.