Dear Ritu,
As you have completed your graduation you have a benefit that you don't need to appear for CPT taken that you had a minimum of 50% in your b.com. So, if you fulfill the eligibility criteria as mentioned being completed your graduation you don't need to appear for CA foundation that is CPT but you can directly apply for the second stage of CA that is IPCC, So you need to fill the form directly for IPCC and not for CPT, after completing your IPCC you might appear for CA Finals, Best of luck, Hope this answer might help you.