I just want to ask that...currently my post-graduation is running so after this I want to do my master in abroad so what should I do?

See, if you are already doing your post-graduation, then it is already considered for the master's. But there are various reasons for which students pursue a double masters in a certain subject, or field to either gain more expertise and skills or to get a better package than the one after a single master's. In my opinion, if the second one is the reason for a student to pursue a double master's, then I would suggest that person should drop off the plan and find a good job, work on the skills and climb the ladder. 

But if you want to pursue it for better skills, abilities, knowledge and network, then here are some things that you should follow: 

• Prepare for GMAT/GRE, whatever entrance exam is mandated by the university. 
• Make a list of good universities and check their eligibility criteria. 
• There are some countries where a double master's is not allowed, so strike off the university of that country from your list. 
• Prepare for IELTS or TOEFL, or look for universities that do not require the IELTS score of the student. 
• Prepare the necessary documents like SOP, LOR and essays for your program application. 

The decision of doing a Double master's is a tough one, what made you opt for a double master's?