First of all, you need to decide which Country you want to opt for an MBA abroad.
Say for example, if you want to opt USA,UK, you should start preparation for
IELTS/TOEFL, GMAT etc.
Basically, university require 1st / 2:1 or 2:2 (Grade) Graduation degree with GMAT Score & Some work Experience in respective field.
If you want to build your career overseas, UK is also an option as good as USA, because of quality education, high learned faculty and world level infrastructure and procedures. Although GMAT is required for UK, but there are alternate pathways for getting into UK Masters program. You may do an MBA without GMAT from best universities of U.K.
Singapore : Is fast gaining an important place as a study abroad destination. It is ranked as the one of the top 5 student cities in Asia and has some of the top universities to boast about.
Like any other MBA, institutes require a GMAT and English proficiency for admission to MBA in Singapore.
Hope this helps
Best of Luck