Hello, 
I assume you are asking about NEET. 
To participate in open round of counselling, you have to clear the cutoff and clear all the eligiblity criteria that is age and domicile(residence) related.
Some states like Karnataka are open states and allow students of other states to take part in their state counselling. 

Follow this link for more
https://www.google.com/amp/s/medicine.careers360.com/articles/neet-counselling/amp
Good luck