Skipper's license (up to 12m, up to 15t)
To manage a sailing yacht, of course, you need to be trained. First of all, you need it yourself. The process is similar to studying at a driving school — you go through theory and practice, learn the rules of the divergence of ships at sea, navigation, yacht and engine design, and much more, and then go through a week (or 10-day) practice at sea.
The decision on whether you will get the rights or not will be made by a licensed instructor who conducts the practice.