can i do with isc board m.b.a after 12th
See, Masters of Business Administration or MBA is a masters level course, which essentially means that you'll have to complete a Bachelors level course before pursing it. Since ISC board's class XIIth examination is not equivalent to a bachelors course, thus you cannot directly go for an MBA right after class XIIth.
Hope I have answered your question. All the best!