Some pilots ask an transition altiude. So far I know is that altiude in USA 18.000 Feet (in the netherlands it is 3500 Feet)and it’s the altiude you most set you airpress at 1013 (not sure).
Is that good or not, and
Pleas explain the transition command and how to use it as an ATC
@dush19 improve this topic where it is needed please.