How to find ST caste certificate ?
You can get ST caste certificate from the nearest Village Office/Thahasildar Office /Village Revenue Officer etc. or Common Sevice Centre like Akshaya/Nadakacheri/Meeseva etc. to know the status of it.
As you have not mentioned about the State, I cannot exactly help you with the department.
The process to get Caste Certificate in few of the States are mentioned below. If you belong to any of the States, you can see the process from there.