Dear Raman,

C. A. Course comprises of 4 Important Levels

1) Common Proficiency Test (CPT)
2) Integrated Professional Competence Course (IPCC)/IPCE
3) Three years Articleship/ Training under a Practicing C.A
4) C. A. Final
You have to Register with the Institute of Chartered Accountants of India (ICAI) for Common Proficiency Test (CPT) in order to write CA CPT exam.

To know in detail you can alos refer below link

https://finance.careers360.com/articles/ca-cpt?icn=cpt_article&ici=cpt_exam_rdmrvp

Good Luck!!