if i am studing in class 12 and i want to give this exam but the condition is 12 pass so how to give

Dear aspirant, as per the eligibility criteria released by The Directorate General of Medical Services (Army) Candidates appearing for their class 12 or equivalent exam during the current academic session may also apply provisionally. This simply means that you can also apply for this exam.

Also, Selected candidates will have to furnish proof of passing the qualifying examination with requisite subjects and marks prior to admissions.

You can check this link for more information
All the best

Hope this helps