Hello,
IRMA is the name of the college - Institute of Rural Management Anand, that's located in Anand, Gujarat. It's the only and best college in India for Rural Management.

IRMASAT is a social aptitude exam conducted by IRMA to test your social knowledge regarding various schemes and activities run for Rural and social development in India, diverse and Various pioneers in bringing about changes, dates and milestones in societal development. These are various kinds of questions asked in the paper. It's a 40 mark paper that consists of multiple choice questions, few direct questions and few informative passage based questions.

IRMASAT will be conducted post CAT/XAT results in the month of February (mid Feb) and based upon you clearing the cutoff in CAT/XAT exams you will be eligible for IRMASAT.

Hope this helps!
All the best!!