Polytechnic

No, you can't. You need to complete Diploma in the same field or a field related to it.

You can get a degree in any field and try for the entrance tests like SSC, UPSC, bank, etc.

You should be a graduate to apply for MBA. Diploma won't work. There is a set hierarchy.

Hi Akash,
The term graduation means Master's degree abroad. You can enroll into a PG course only after you complete your Bachelor degree. Admission process and requirements will depend on the country and university. International applicants must take IELTS or TOEFL to meet language requirements. Kindly, decide where to apply and then visit university requirements on their websites.
Feel free to revert.

If you can show your salary slips at the time of the interview then it would be considered as work experience.

You are not eligible to apply for MBA as you are just a Diploma holder. It is a Master's degree program and the minimum eligibility requirement is degree in any discipline from a recognized university with 50% marks.

Hello Atharva,
You do not meet the eligibility criteria, hence you cannot appear for this entrance exam. Your best chance to pursue degree is to get good marks in Diploma and bid for admission in the 2nd year of engineering.

You should submit the online application during the time of admission. Your allotment is based on your 10th marks. If you have completed ITI/VHSC you have more chances to get a government seat.

Directorate of Technical Education in most of states conduct Join Entrance Examination (JEE) for Diploma level courses. The minimum academic qualification to appear in JEE is a pass in the final examination of High School (with the subject science and maths-II) from recognized board or equivalent. You may look for details in your own Atate Government's website for details.