Hello sir,

Hope you are doing great.

In general, if you have opted at the time of application form  that you belong to a specific caste category, then you are supposed to submit the caste certificate during the admission process. However, you can give them a written statement specifying that you will submit the caste certificate in future. But remember that, it is completely at the discretion of the college authorities as to accept or reject the written statement. So, after taking their permission, provide the written statement.

Hope this helps!