Hey there! Concourse J will be used if you are traveling out of the Royal Air Maroc Airlines MIA Terminal. Although it can get crowded during peak hours, the check-in procedure is usually easy. The terminal has cozy waiting areas, and security lines move at a reasonable speed. There are plenty of places to eat and buy close by, so you won't be bored before your trip. A hassle-free encounter is guaranteed by the staff's professionalism and helpfulness. 
for more: https://www.terminalfind.com/royal-air-maroc-airlines/royal-air-maroc-airlines-mia-terminal-miami-international-airport/