Diploma

Eligibility Criteria for PGDMM in Materials Management is you should have 3 yr Minimum graduate degree from any discipline. On the website of Indian Institute of Materials Management you will find a Application form for the admission.
Fill the form and submit.

You can't do B.Tech in foreign countries after only doing Diploma. They don't have lateral entry system. If you have passed 12th then, you can apply.

Yes, you can apply but you need to clear the entrance exam and you need at least 50% marks in your Diploma course.

Hello Jen's,
My advise us don't go for distance education in engineering. In recent judgement, Supreme Court of India has cancelled engineering degrees conferred almost 10-15 years back by distance education universities.