Why for admission in MHA students those are graduated from medical field such as MBBS, Physiotherapy, BDS are preferred rather than other graduates?

Content.

If you have a medical degree, you are versed in anatomy, physiology, terminology, equipment, etc. You'd also be able to communicate and relate to the physicians that are working in the environment, often with distinguished positions within the organization.

These are all very important subjects to be well versed in for hospital administration.