I wish to do MS in mech engg abroad.which country should i prefer considering educational faculty,economy and safety and what prep should do

Dear Shreta, Germany is the best choice for Mech if you have 75% plus in your BE, if not then select Australia if you are looking at PSW and PR or else low cost and 1 year MS then choose UK but there is no stay back or PSW.

I strongly suggest you first consider USA, then Canada, then Ireland, then Australia and then NZ. This is in case you look at applying for a Post-Study Work Visa. In case you do not require a PSW, UK always first, then USA, then Ireland, then the rest. Hope this helps. Thanks!