M.Phil

Yes, you can go for PhD after completing MBA. There is no restriction.

Your question is not clear, please specify what details of the UGC guidelines do you require?

You can go either of the two. Generally University first offers Mphil and than PhD. M.Phil is "Master of Philosophy". It is an advanced post graduate research degree. You can contact your University from where you did M.Sc. They might be providing a research degree in your field. It can seek you a job in either government or a private college or University. Similarly PhD is done after M.Phil. A Doctor of Philosophy is the highest academic degree awarded by universities. In most countries PhDs are awarded for programs across the whole breadth of academic fields.

You are advised to appear for the NET examination. It is a test to determine eligibility for college and university level lectureship and for the award of Junior Research Fellowship. You may also evaluate doing Ph.D.

You need to complete PG in the area in which you intend to pursue M.Phil.
Since you have done MCA, you can pursue M.Phil in a field related to computer application only.

M.Phil is the same as doing Ph.D. After completing your M.Phil in maths, you have a whole range of options available. You could join the teaching line or become a project manager, lab technician and research assistant. Individuals with M.Phil degree can be successful in life. Many carry on to become directors of higher educational bodies, Managers, recruitment managers, etc.