Hello Bharti,
As per my opinion CA Course is most difficult course compare to CMA and other course. But CA scope is better than the CMA course and other.  There is no doubt to say that ‘CA’ holder can earn more than any other.After completion of the chartered accountancy course they can work as chartered accountants at various organizations and can earn from 2 lakhs to 10 lakhs per annum
After completion of the ICWA course student can continue his career as cost and management accountant. ICWA completed candidate can earn salary between l lakh to 6 lakhs per annum by joining in a managerial position.
Alternatively they can also join as internal auditors in the organizations and can earn 4 lakhs to 6 lakhs salary per month.