Hello

If you did your 12th in Maharashtra but have an OBC certificate from Uttar Pradesh, then you can only use the OBC reservation in UP, not in Maharashtra.
This is because each state accepts only its own state-issued caste certificate for state quota medical seats.
So, in Maharashtra MBBS counselling, you will be considered the General category unless you have a Maharashtra-issued OBC certificate.
But if you apply for MBBS seats through UP state counselling, your UP OBC certificate will be valid.
For All India Quota (AIQ) 15, only a central OBC-NCL certificate is needed.