Hello,
You have not mentioned  anything about the course or college or the exams you have applied.
I am just giving you a general idea.
Please let me know the details so that I can help you more.
Once you get your allotment letter for your college, you have to pay the fees for the course right after that. You will also require below documents at the time of document verification.
1. Three Passport size photograph of the applicant

2. Class X certificate/marksheet containing Date of Birth

3. Class XII Mark Sheet, if results have been announced

4. SC/ST/PwD/CW/KM Certificate (in the name of the Applicant) issued by the competent authority

5. OBC (Non-Creamy Layer) Certificate (in the name of the Applicant) issued on or after March 31, 2019. The OBC caste must be included in Central list issued by the Government of India

6. EWS Certificate issued by SDM certifying the applicant can claim reservation under this category, dated March 31, 2019 or later

7. Sports and/or ECA certificates, if applying under these categories

Hope it helps